diff --git a/b2g/components/test/Makefile.in b/b2g/components/test/Makefile.in
deleted file mode 100644
index 29a9eedf6ac..00000000000
--- a/b2g/components/test/Makefile.in
+++ /dev/null
@@ -1,16 +0,0 @@
-# vim: noexpandtab ts=8 sw=8
-#
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-DEPTH		= @DEPTH@
-topsrcdir	= @top_srcdir@
-srcdir		= @srcdir@
-VPATH		= @srcdir@
-relativesrcdir = @relativesrcdir@
-FAIL_ON_WARNINGS := 1
-
-include $(DEPTH)/config/autoconf.mk
-
-include $(topsrcdir)/config/rules.mk
diff --git a/b2g/components/test/moz.build b/b2g/components/test/moz.build
index 556309ce409..99d23a40921 100644
--- a/b2g/components/test/moz.build
+++ b/b2g/components/test/moz.build
@@ -7,3 +7,6 @@
 MODULE = 'B2GComponents'
 
 XPCSHELL_TESTS_MANIFESTS += ['unit/xpcshell.ini']
+
+FAIL_ON_WARNINGS = True
+
diff --git a/content/base/src/Makefile.in b/content/base/src/Makefile.in
index 8cdec868b97..417b48dbc57 100644
--- a/content/base/src/Makefile.in
+++ b/content/base/src/Makefile.in
@@ -13,8 +13,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME	= gkconbase_s
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 ifdef MOZ_WEBRTC
 LOCAL_INCLUDES += \
 		-I$(topsrcdir)/netwerk/sctp/datachannel \
diff --git a/content/base/src/moz.build b/content/base/src/moz.build
index afaa6dd8354..a149aec820d 100644
--- a/content/base/src/moz.build
+++ b/content/base/src/moz.build
@@ -169,3 +169,6 @@ EXTRA_PP_COMPONENTS += [
 EXTRA_JS_MODULES += [
     'CSPUtils.jsm',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/content/canvas/compiledtest/Makefile.in b/content/canvas/compiledtest/Makefile.in
index 2baa1df2866..b1858fe42fb 100644
--- a/content/canvas/compiledtest/Makefile.in
+++ b/content/canvas/compiledtest/Makefile.in
@@ -7,8 +7,6 @@ topsrcdir := @top_srcdir@
 srcdir := @srcdir@
 VPATH := @srcdir@
 
-FAIL_ON_WARNINGS = 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LOCAL_INCLUDES := \
diff --git a/content/canvas/compiledtest/moz.build b/content/canvas/compiledtest/moz.build
index 0f7f9476252..0f03ae80f45 100644
--- a/content/canvas/compiledtest/moz.build
+++ b/content/canvas/compiledtest/moz.build
@@ -8,3 +8,5 @@ CPP_UNIT_TESTS += [
     'TestWebGLElementArrayCache.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/canvas/src/Makefile.in b/content/canvas/src/Makefile.in
index 10aafe5dd7a..e3f47d8ffcc 100644
--- a/content/canvas/src/Makefile.in
+++ b/content/canvas/src/Makefile.in
@@ -13,8 +13,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME	= gkconcvs_s
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY  = 1
-FAIL_ON_WARNINGS = 1
-
 ifdef MOZ_WEBGL
 LOCAL_INCLUDES += \
 	-I$(topsrcdir)/js/xpconnect/wrappers \
diff --git a/content/canvas/src/moz.build b/content/canvas/src/moz.build
index a7971dfff82..3b1c1427630 100644
--- a/content/canvas/src/moz.build
+++ b/content/canvas/src/moz.build
@@ -73,3 +73,6 @@ else:
     CPP_SOURCES += [
         'WebGLContextNotSupported.cpp',
     ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/content/events/src/Makefile.in b/content/events/src/Makefile.in
index b24dc90fb0c..8dc9ad447ef 100644
--- a/content/events/src/Makefile.in
+++ b/content/events/src/Makefile.in
@@ -13,8 +13,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME	= gkconevents_s
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY  = 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 include $(topsrcdir)/ipc/chromium/chromium-config.mk
 
diff --git a/content/events/src/moz.build b/content/events/src/moz.build
index 143b8f6b540..06ac1db0c42 100644
--- a/content/events/src/moz.build
+++ b/content/events/src/moz.build
@@ -66,3 +66,6 @@ CPP_SOURCES += [
 
 if CONFIG['MOZ_WEBSPEECH']:
     CPP_SOURCES += ['SpeechRecognitionError.cpp']
+
+FAIL_ON_WARNINGS = True
+
diff --git a/content/html/content/src/Makefile.in b/content/html/content/src/Makefile.in
index 6fd3699ddbd..d426ab32361 100644
--- a/content/html/content/src/Makefile.in
+++ b/content/html/content/src/Makefile.in
@@ -13,8 +13,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME	= gkconhtmlcon_s
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 include $(topsrcdir)/ipc/chromium/chromium-config.mk
 
diff --git a/content/html/content/src/moz.build b/content/html/content/src/moz.build
index 6e873616e7f..8212d436a45 100644
--- a/content/html/content/src/moz.build
+++ b/content/html/content/src/moz.build
@@ -154,3 +154,5 @@ CPP_SOURCES += [
     'nsTextEditorState.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/html/document/src/Makefile.in b/content/html/document/src/Makefile.in
index ef5a57c9e8b..8657240f049 100644
--- a/content/html/document/src/Makefile.in
+++ b/content/html/document/src/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
 LOCAL_INCLUDES += \
diff --git a/content/html/document/src/moz.build b/content/html/document/src/moz.build
index d277ee6c263..80520f44d48 100644
--- a/content/html/document/src/moz.build
+++ b/content/html/document/src/moz.build
@@ -25,3 +25,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'gkconhtmldoc_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/mathml/content/src/Makefile.in b/content/mathml/content/src/Makefile.in
index 25afcb68348..63de0e78b7a 100644
--- a/content/mathml/content/src/Makefile.in
+++ b/content/mathml/content/src/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME	= gkcontentmathml_s
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 include $(topsrcdir)/ipc/chromium/chromium-config.mk
 
diff --git a/content/mathml/content/src/moz.build b/content/mathml/content/src/moz.build
index cfd45e762bf..6dd667b1e39 100644
--- a/content/mathml/content/src/moz.build
+++ b/content/mathml/content/src/moz.build
@@ -11,3 +11,5 @@ CPP_SOURCES += [
     'nsMathMLElementFactory.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/media/Makefile.in b/content/media/Makefile.in
index c7f833d497c..4b43651df2b 100644
--- a/content/media/Makefile.in
+++ b/content/media/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME = gkconmedia_s
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/config/rules.mk
 include $(topsrcdir)/ipc/chromium/chromium-config.mk
 
diff --git a/content/media/directshow/Makefile.in b/content/media/directshow/Makefile.in
index 540538e614e..ae7aac70d12 100644
--- a/content/media/directshow/Makefile.in
+++ b/content/media/directshow/Makefile.in
@@ -9,8 +9,6 @@ VPATH		= @srcdir@
 
 include $(DEPTH)/config/autoconf.mk
 
-FAIL_ON_WARNINGS := 1
-
 LIBRARY_NAME	= gkcondirectshow_s
 LIBXUL_LIBRARY 	= 1
 
diff --git a/content/media/directshow/moz.build b/content/media/directshow/moz.build
index d8cd61651c9..6a405dd6b8f 100644
--- a/content/media/directshow/moz.build
+++ b/content/media/directshow/moz.build
@@ -33,3 +33,6 @@ if not CONFIG['MOZ_WEBRTC_IN_LIBXUL']:
         TOPSRCDIR + '/media/webrtc/trunk/webrtc/modules/video_capture/windows/BasePin.cpp',
         TOPSRCDIR + '/media/webrtc/trunk/webrtc/modules/video_capture/windows/MediaType.cpp',
     ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/content/media/encoder/Makefile.in b/content/media/encoder/Makefile.in
index c4e33711a8e..865181c4ce4 100644
--- a/content/media/encoder/Makefile.in
+++ b/content/media/encoder/Makefile.in
@@ -10,7 +10,4 @@ VPATH     = @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS := 1
-
-
 include $(topsrcdir)/config/rules.mk
diff --git a/content/media/encoder/moz.build b/content/media/encoder/moz.build
index ba1eb736acf..cf0ea9304b3 100644
--- a/content/media/encoder/moz.build
+++ b/content/media/encoder/moz.build
@@ -23,3 +23,5 @@ if CONFIG['MOZ_OPUS']:
 
 LIBRARY_NAME = 'gkconencoder_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/media/gstreamer/Makefile.in b/content/media/gstreamer/Makefile.in
index 86cc606de10..0aee85c5965 100644
--- a/content/media/gstreamer/Makefile.in
+++ b/content/media/gstreamer/Makefile.in
@@ -6,8 +6,6 @@ DEPTH		= @DEPTH@
 topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY 	= 1
diff --git a/content/media/gstreamer/moz.build b/content/media/gstreamer/moz.build
index 26e27d86472..09cccea4f76 100644
--- a/content/media/gstreamer/moz.build
+++ b/content/media/gstreamer/moz.build
@@ -23,3 +23,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'gkcongstreamer_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/media/mediasource/Makefile.in b/content/media/mediasource/Makefile.in
index 9c5676c573c..75a112639e5 100644
--- a/content/media/mediasource/Makefile.in
+++ b/content/media/mediasource/Makefile.in
@@ -6,8 +6,6 @@ DEPTH		= @DEPTH@
 topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME	= gkconmediasource_s
diff --git a/content/media/mediasource/moz.build b/content/media/mediasource/moz.build
index 6b1aec7232c..a90461521bd 100644
--- a/content/media/mediasource/moz.build
+++ b/content/media/mediasource/moz.build
@@ -26,3 +26,5 @@ CPP_SOURCES += [
     'SourceBufferList.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/media/moz.build b/content/media/moz.build
index 237e43ae1a2..2ebeb4c4362 100644
--- a/content/media/moz.build
+++ b/content/media/moz.build
@@ -130,6 +130,9 @@ CPP_SOURCES += [
     'WebVTTLoadListener.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
+
 if CONFIG['CPU_ARCH'] == 'arm' and CONFIG['BUILD_ARM_NEON']:
     CPP_SOURCES += [
         'AudioNodeEngineNEON.cpp',
diff --git a/content/media/ogg/Makefile.in b/content/media/ogg/Makefile.in
index 86df1d7589a..5ce55c06d6e 100644
--- a/content/media/ogg/Makefile.in
+++ b/content/media/ogg/Makefile.in
@@ -10,7 +10,4 @@ VPATH		= @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY 	= 1
-FAIL_ON_WARNINGS := 1
-
-
 include $(topsrcdir)/config/rules.mk
diff --git a/content/media/ogg/moz.build b/content/media/ogg/moz.build
index 7b2a721745d..7cbf7048205 100644
--- a/content/media/ogg/moz.build
+++ b/content/media/ogg/moz.build
@@ -22,3 +22,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'gkconogg_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/media/raw/Makefile.in b/content/media/raw/Makefile.in
index 57d9b387556..0990e6e3765 100644
--- a/content/media/raw/Makefile.in
+++ b/content/media/raw/Makefile.in
@@ -11,8 +11,6 @@ VPATH = @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/config/rules.mk
 
 INCLUDES	+= \
diff --git a/content/media/raw/moz.build b/content/media/raw/moz.build
index 54cbeac3f68..a8dabceaf13 100644
--- a/content/media/raw/moz.build
+++ b/content/media/raw/moz.build
@@ -19,3 +19,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'gkconraw_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/media/wave/Makefile.in b/content/media/wave/Makefile.in
index 519c470e12b..bdacd989c36 100644
--- a/content/media/wave/Makefile.in
+++ b/content/media/wave/Makefile.in
@@ -6,8 +6,6 @@ DEPTH		= @DEPTH@
 topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY 	= 1
diff --git a/content/media/wave/moz.build b/content/media/wave/moz.build
index b44832b335e..ca2ede1e260 100644
--- a/content/media/wave/moz.build
+++ b/content/media/wave/moz.build
@@ -18,3 +18,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'gkconwave_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/media/webaudio/Makefile.in b/content/media/webaudio/Makefile.in
index dca187ece60..2e675ecfe7e 100644
--- a/content/media/webaudio/Makefile.in
+++ b/content/media/webaudio/Makefile.in
@@ -11,7 +11,5 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME   := gkconwebaudio_s
 LIBXUL_LIBRARY := 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/config/rules.mk
 include $(topsrcdir)/ipc/chromium/chromium-config.mk
diff --git a/content/media/webaudio/compiledtest/Makefile.in b/content/media/webaudio/compiledtest/Makefile.in
index ca8cc642cb8..4dd0d37710f 100644
--- a/content/media/webaudio/compiledtest/Makefile.in
+++ b/content/media/webaudio/compiledtest/Makefile.in
@@ -10,8 +10,6 @@ relativesrcdir := @relativesrcdir@
 
 include $(DEPTH)/config/autoconf.mk
 
-FAIL_ON_WARNINGS = 1
-
 LOCAL_INCLUDES := -I$(srcdir)/..
 
 include $(topsrcdir)/config/rules.mk
diff --git a/content/media/webaudio/compiledtest/moz.build b/content/media/webaudio/compiledtest/moz.build
index 8d38be629e9..1b079ac5ce9 100644
--- a/content/media/webaudio/compiledtest/moz.build
+++ b/content/media/webaudio/compiledtest/moz.build
@@ -8,3 +8,5 @@ CPP_UNIT_TESTS += [
     'TestAudioEventTimeline.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/media/webaudio/moz.build b/content/media/webaudio/moz.build
index 92a331a730a..bf44474ec85 100644
--- a/content/media/webaudio/moz.build
+++ b/content/media/webaudio/moz.build
@@ -84,3 +84,5 @@ CPP_SOURCES += [
     'WebAudioUtils.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/media/webm/Makefile.in b/content/media/webm/Makefile.in
index 22d53ba6ae0..d8e73b908a3 100644
--- a/content/media/webm/Makefile.in
+++ b/content/media/webm/Makefile.in
@@ -6,8 +6,6 @@ DEPTH		= @DEPTH@
 topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY 	= 1
diff --git a/content/media/webm/moz.build b/content/media/webm/moz.build
index dea61fe0d72..a9b1f22165e 100644
--- a/content/media/webm/moz.build
+++ b/content/media/webm/moz.build
@@ -19,3 +19,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'gkconwebm_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/media/webspeech/synth/Makefile.in b/content/media/webspeech/synth/Makefile.in
index 2932ae3d145..505406ba8a1 100644
--- a/content/media/webspeech/synth/Makefile.in
+++ b/content/media/webspeech/synth/Makefile.in
@@ -6,9 +6,6 @@ DEPTH            := @DEPTH@
 topsrcdir        := @top_srcdir@
 srcdir           := @srcdir@
 VPATH            := @srcdir@
-FAIL_ON_WARNINGS := 1
-
-
 include $(DEPTH)/config/autoconf.mk
 include $(topsrcdir)/dom/dom-config.mk
 
diff --git a/content/media/webspeech/synth/moz.build b/content/media/webspeech/synth/moz.build
index ae135a7ccf0..46609f0f8c4 100644
--- a/content/media/webspeech/synth/moz.build
+++ b/content/media/webspeech/synth/moz.build
@@ -42,3 +42,6 @@ IPDL_SOURCES += [
     'ipc/PSpeechSynthesis.ipdl',
     'ipc/PSpeechSynthesisRequest.ipdl',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/content/media/wmf/Makefile.in b/content/media/wmf/Makefile.in
index 8f6dd8fb857..48665405f08 100644
--- a/content/media/wmf/Makefile.in
+++ b/content/media/wmf/Makefile.in
@@ -6,8 +6,6 @@ DEPTH		= @DEPTH@
 topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY 	= 1
diff --git a/content/media/wmf/moz.build b/content/media/wmf/moz.build
index 6f73110ca77..1b13aea2fb9 100644
--- a/content/media/wmf/moz.build
+++ b/content/media/wmf/moz.build
@@ -23,3 +23,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'gkconwmf_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/smil/Makefile.in b/content/smil/Makefile.in
index 8be207b28d9..4137896ddf9 100644
--- a/content/smil/Makefile.in
+++ b/content/smil/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME	= gkconsmil_s
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 LOCAL_INCLUDES += 	\
 		-I$(srcdir)/../base/src \
 		-I$(srcdir)/../../layout/style \
diff --git a/content/smil/moz.build b/content/smil/moz.build
index ed9f2281a76..ca099a10c04 100644
--- a/content/smil/moz.build
+++ b/content/smil/moz.build
@@ -61,3 +61,5 @@ CPP_SOURCES += [
     'nsSMILValue.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/svg/content/src/Makefile.in b/content/svg/content/src/Makefile.in
index fbb807af718..25e0d81cce8 100644
--- a/content/svg/content/src/Makefile.in
+++ b/content/svg/content/src/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME	= gkcontentsvg_s
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS	= 1
-
 include $(topsrcdir)/config/rules.mk
 include $(topsrcdir)/ipc/chromium/chromium-config.mk
 
diff --git a/content/svg/content/src/moz.build b/content/svg/content/src/moz.build
index 32956b746e3..fa0eba9037c 100644
--- a/content/svg/content/src/moz.build
+++ b/content/svg/content/src/moz.build
@@ -244,3 +244,5 @@ CPP_SOURCES += [
     'nsSVGViewBox.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/svg/document/src/Makefile.in b/content/svg/document/src/Makefile.in
index 9bf4e63da79..c1379e2f238 100644
--- a/content/svg/document/src/Makefile.in
+++ b/content/svg/document/src/Makefile.in
@@ -11,8 +11,6 @@ VPATH		= @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
 INCLUDES	+= \
diff --git a/content/svg/document/src/moz.build b/content/svg/document/src/moz.build
index b1baa01f22f..1acbbbe49d3 100644
--- a/content/svg/document/src/moz.build
+++ b/content/svg/document/src/moz.build
@@ -16,3 +16,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'gkconsvgdoc_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/xbl/src/Makefile.in b/content/xbl/src/Makefile.in
index 0df5822ca7c..94105b980e6 100644
--- a/content/xbl/src/Makefile.in
+++ b/content/xbl/src/Makefile.in
@@ -13,8 +13,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME	= gkconxbl_s
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
 LOCAL_INCLUDES	= \
diff --git a/content/xbl/src/moz.build b/content/xbl/src/moz.build
index e613e319253..10fa50a5f72 100644
--- a/content/xbl/src/moz.build
+++ b/content/xbl/src/moz.build
@@ -36,3 +36,5 @@ CPP_SOURCES += [
     'XBLChildrenElement.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/xml/content/src/Makefile.in b/content/xml/content/src/Makefile.in
index 2ccb39e0761..2a325fe3221 100644
--- a/content/xml/content/src/Makefile.in
+++ b/content/xml/content/src/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
 INCLUDES	+= \
diff --git a/content/xml/content/src/moz.build b/content/xml/content/src/moz.build
index 1d3ce63b4ba..a36a89a124e 100644
--- a/content/xml/content/src/moz.build
+++ b/content/xml/content/src/moz.build
@@ -22,3 +22,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'gkconxmlcon_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/xml/document/src/Makefile.in b/content/xml/document/src/Makefile.in
index 481b9c2dbb0..b439a0c106f 100644
--- a/content/xml/document/src/Makefile.in
+++ b/content/xml/document/src/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
 LOCAL_INCLUDES	= \
diff --git a/content/xml/document/src/moz.build b/content/xml/document/src/moz.build
index 2a00a1385a8..a117870b157 100644
--- a/content/xml/document/src/moz.build
+++ b/content/xml/document/src/moz.build
@@ -19,3 +19,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'gkconxmldoc_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/xslt/src/base/Makefile.in b/content/xslt/src/base/Makefile.in
index 70ca9d5dd33..b998d654e42 100644
--- a/content/xslt/src/base/Makefile.in
+++ b/content/xslt/src/base/Makefile.in
@@ -10,8 +10,6 @@ VPATH           = @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
 INCLUDES += \
diff --git a/content/xslt/src/base/moz.build b/content/xslt/src/base/moz.build
index cc783af3dd1..272c27cc365 100644
--- a/content/xslt/src/base/moz.build
+++ b/content/xslt/src/base/moz.build
@@ -16,3 +16,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'txbase_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/xslt/src/xml/Makefile.in b/content/xslt/src/xml/Makefile.in
index 590169fc38c..5ea8eda299a 100644
--- a/content/xslt/src/xml/Makefile.in
+++ b/content/xslt/src/xml/Makefile.in
@@ -10,8 +10,6 @@ VPATH           = @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
 INCLUDES += \
diff --git a/content/xslt/src/xml/moz.build b/content/xslt/src/xml/moz.build
index 9a0fd8be184..e6202e1ade7 100644
--- a/content/xslt/src/xml/moz.build
+++ b/content/xslt/src/xml/moz.build
@@ -13,3 +13,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'txxml_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/xslt/src/xpath/Makefile.in b/content/xslt/src/xpath/Makefile.in
index 1608dc477d1..868af65fdf7 100644
--- a/content/xslt/src/xpath/Makefile.in
+++ b/content/xslt/src/xpath/Makefile.in
@@ -10,8 +10,6 @@ VPATH           = @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
 INCLUDES += \
diff --git a/content/xslt/src/xpath/moz.build b/content/xslt/src/xpath/moz.build
index 20679a9abcb..cf2fa290241 100644
--- a/content/xslt/src/xpath/moz.build
+++ b/content/xslt/src/xpath/moz.build
@@ -49,3 +49,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'txxpath_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/xslt/src/xslt/Makefile.in b/content/xslt/src/xslt/Makefile.in
index 72cfb09afa6..3b4cca3b334 100644
--- a/content/xslt/src/xslt/Makefile.in
+++ b/content/xslt/src/xslt/Makefile.in
@@ -10,7 +10,6 @@ VPATH           = @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
 
 # For nsDependentJSString
 LOCAL_INCLUDES += \
diff --git a/content/xslt/src/xslt/moz.build b/content/xslt/src/xslt/moz.build
index f864406552f..d0860baf19e 100644
--- a/content/xslt/src/xslt/moz.build
+++ b/content/xslt/src/xslt/moz.build
@@ -46,3 +46,5 @@ EXTRA_COMPONENTS += [
 
 LIBRARY_NAME = 'txxslt_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/content/xul/content/src/Makefile.in b/content/xul/content/src/Makefile.in
index 1b90983ca45..398004ebb15 100644
--- a/content/xul/content/src/Makefile.in
+++ b/content/xul/content/src/Makefile.in
@@ -7,8 +7,6 @@ DEPTH		= @DEPTH@
 topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
-FAIL_ON_WARNINGS = 1
-
 include $(DEPTH)/config/autoconf.mk
 
 ifdef MOZ_XUL
@@ -16,8 +14,6 @@ MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY	= 1
 endif
 
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
 LOCAL_INCLUDES	= \
diff --git a/content/xul/content/src/moz.build b/content/xul/content/src/moz.build
index 068e5a0f062..1b70a59c45d 100644
--- a/content/xul/content/src/moz.build
+++ b/content/xul/content/src/moz.build
@@ -13,3 +13,6 @@ if CONFIG['MOZ_XUL']:
         'nsXULContextMenuBuilder.cpp',
     ]
     LIBRARY_NAME = 'gkconxulcon_s'
+
+FAIL_ON_WARNINGS = True
+
diff --git a/content/xul/document/src/Makefile.in b/content/xul/document/src/Makefile.in
index 2cb31b06748..b8cdfe75429 100644
--- a/content/xul/document/src/Makefile.in
+++ b/content/xul/document/src/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
 LOCAL_INCLUDES	= -I$(srcdir)/../../../base/src \
diff --git a/content/xul/document/src/moz.build b/content/xul/document/src/moz.build
index 1c666c03ce2..6eb1d60fa5a 100644
--- a/content/xul/document/src/moz.build
+++ b/content/xul/document/src/moz.build
@@ -21,3 +21,5 @@ if CONFIG['MOZ_XUL']:
 
 LIBRARY_NAME = 'gkconxuldoc_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/docshell/base/Makefile.in b/docshell/base/Makefile.in
index e3bc7131a1b..0ffe878c3b6 100644
--- a/docshell/base/Makefile.in
+++ b/docshell/base/Makefile.in
@@ -10,7 +10,6 @@ VPATH = @srcdir@
 
 include $(DEPTH)/config/autoconf.mk
 
-FAIL_ON_WARNINGS := 1
 LIBRARY_NAME   = basedocshell_s
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY = 1
diff --git a/docshell/base/moz.build b/docshell/base/moz.build
index 1895adea1fd..cbf67d31d75 100644
--- a/docshell/base/moz.build
+++ b/docshell/base/moz.build
@@ -62,3 +62,5 @@ CPP_SOURCES += [
     'nsWebNavigationInfo.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/docshell/shistory/src/Makefile.in b/docshell/shistory/src/Makefile.in
index 7fecb85a394..f4de7098fd8 100644
--- a/docshell/shistory/src/Makefile.in
+++ b/docshell/shistory/src/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
 LOCAL_INCLUDES += -I$(srcdir)/../../base
diff --git a/docshell/shistory/src/moz.build b/docshell/shistory/src/moz.build
index f792acf65d7..c211c4dc987 100644
--- a/docshell/shistory/src/moz.build
+++ b/docshell/shistory/src/moz.build
@@ -19,3 +19,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'shistory_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/activities/src/Makefile.in b/dom/activities/src/Makefile.in
index 385b8720be1..7391ab0d925 100644
--- a/dom/activities/src/Makefile.in
+++ b/dom/activities/src/Makefile.in
@@ -11,8 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME     = dom_activities_s
 LIBXUL_LIBRARY   = 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/dom/dom-config.mk
 
 include $(topsrcdir)/config/rules.mk
diff --git a/dom/activities/src/moz.build b/dom/activities/src/moz.build
index b107bcb5d84..48e48f1af10 100644
--- a/dom/activities/src/moz.build
+++ b/dom/activities/src/moz.build
@@ -27,3 +27,6 @@ EXTRA_JS_MODULES += [
     'ActivitiesService.jsm',
     'ActivitiesServiceFilter.jsm',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/activities/tests/Makefile.in b/dom/activities/tests/Makefile.in
deleted file mode 100644
index e8a194c897c..00000000000
--- a/dom/activities/tests/Makefile.in
+++ /dev/null
@@ -1,15 +0,0 @@
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-DEPTH           = @DEPTH@
-topsrcdir       = @top_srcdir@
-srcdir          = @srcdir@
-VPATH           = @srcdir@
-relativesrcdir  = @relativesrcdir@
-
-FAIL_ON_WARNINGS := 1
-
-include $(DEPTH)/config/autoconf.mk
-
-include $(topsrcdir)/config/rules.mk
diff --git a/dom/activities/tests/moz.build b/dom/activities/tests/moz.build
index 191c90f0b92..b984ece4aa0 100644
--- a/dom/activities/tests/moz.build
+++ b/dom/activities/tests/moz.build
@@ -5,3 +5,6 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 XPCSHELL_TESTS_MANIFESTS += ['unit/xpcshell.ini']
+
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/alarm/Makefile.in b/dom/alarm/Makefile.in
index f7926ebbc28..c78da2609c6 100644
--- a/dom/alarm/Makefile.in
+++ b/dom/alarm/Makefile.in
@@ -11,8 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME        = domalarm_s
 LIBXUL_LIBRARY      = 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/dom/dom-config.mk
 
 
diff --git a/dom/alarm/moz.build b/dom/alarm/moz.build
index d851490f445..86b6b24109f 100644
--- a/dom/alarm/moz.build
+++ b/dom/alarm/moz.build
@@ -32,3 +32,6 @@ EXTRA_JS_MODULES += [
     'AlarmDB.jsm',
     'AlarmService.jsm',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/audiochannel/Makefile.in b/dom/audiochannel/Makefile.in
index 2fd96f5d3b5..bcd8c65fa73 100644
--- a/dom/audiochannel/Makefile.in
+++ b/dom/audiochannel/Makefile.in
@@ -22,8 +22,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME     = domaudiochannel_s
 LIBXUL_LIBRARY = 1
 EXPORT_LIBRARY = 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/config/rules.mk
 include $(topsrcdir)/ipc/chromium/chromium-config.mk
 
diff --git a/dom/audiochannel/moz.build b/dom/audiochannel/moz.build
index 5b116f5a320..c99354af855 100644
--- a/dom/audiochannel/moz.build
+++ b/dom/audiochannel/moz.build
@@ -27,3 +27,5 @@ CPP_SOURCES += [
     'AudioChannelServiceChild.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/audiochannel/tests/Makefile.in b/dom/audiochannel/tests/Makefile.in
deleted file mode 100644
index 0659b837571..00000000000
--- a/dom/audiochannel/tests/Makefile.in
+++ /dev/null
@@ -1,16 +0,0 @@
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-DEPTH		= @DEPTH@
-topsrcdir	= @top_srcdir@
-srcdir		= @srcdir@
-VPATH		= @srcdir@
-relativesrcdir = @relativesrcdir@
-
-include $(DEPTH)/config/autoconf.mk
-
-FAIL_ON_WARNINGS = 1
-
-include $(topsrcdir)/config/rules.mk
-
diff --git a/dom/audiochannel/tests/moz.build b/dom/audiochannel/tests/moz.build
index 35da34275ea..e1148d182ff 100644
--- a/dom/audiochannel/tests/moz.build
+++ b/dom/audiochannel/tests/moz.build
@@ -10,3 +10,5 @@ CPP_UNIT_TESTS += [
     'TestAudioChannelService.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/base/Makefile.in b/dom/base/Makefile.in
index dcdf8c79270..026f6006342 100644
--- a/dom/base/Makefile.in
+++ b/dom/base/Makefile.in
@@ -12,9 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME	= jsdombase_s
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS := 1
-
-
 include $(topsrcdir)/dom/dom-config.mk
 
 ifdef MOZ_JSDEBUGGER
diff --git a/dom/base/moz.build b/dom/base/moz.build
index 469970f40c2..277cc88bed2 100644
--- a/dom/base/moz.build
+++ b/dom/base/moz.build
@@ -108,3 +108,6 @@ EXTRA_JS_MODULES += [
     'IndexedDBHelper.jsm',
     'ObjectWrapper.jsm',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/battery/Makefile.in b/dom/battery/Makefile.in
index 67a18432487..0dbb06b967f 100644
--- a/dom/battery/Makefile.in
+++ b/dom/battery/Makefile.in
@@ -11,8 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME     = dom_battery_s
 LIBXUL_LIBRARY   = 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/dom/dom-config.mk
 
 LOCAL_INCLUDES = \
diff --git a/dom/battery/moz.build b/dom/battery/moz.build
index 732603cdd71..bd246cf7830 100644
--- a/dom/battery/moz.build
+++ b/dom/battery/moz.build
@@ -15,3 +15,5 @@ CPP_SOURCES += [
     'BatteryManager.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/bindings/Makefile.in b/dom/bindings/Makefile.in
index 3465285eeee..c387c3d536b 100644
--- a/dom/bindings/Makefile.in
+++ b/dom/bindings/Makefile.in
@@ -13,7 +13,6 @@ LIBRARY_NAME     = dombindings_s
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY   = 1
 EXPORT_LIBRARY   = 1
-FAIL_ON_WARNINGS := 1
 
 # Need this to find all our DOM source files.
 include $(topsrcdir)/dom/dom-config.mk
diff --git a/dom/bindings/moz.build b/dom/bindings/moz.build
index 0ef597cfc05..7b7a1cae625 100644
--- a/dom/bindings/moz.build
+++ b/dom/bindings/moz.build
@@ -25,3 +25,6 @@ EXPORTS.mozilla.dom += [
     'PrimitiveConversions.h',
     'TypedArray.h',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/bluetooth/Makefile.in b/dom/bluetooth/Makefile.in
index b199e4133df..6e62298b7cf 100644
--- a/dom/bluetooth/Makefile.in
+++ b/dom/bluetooth/Makefile.in
@@ -16,8 +16,6 @@ DEPTH            = @DEPTH@
 topsrcdir        = @top_srcdir@
 srcdir           = @srcdir@
 VPATH            = @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 include $(topsrcdir)/dom/dom-config.mk
 
diff --git a/dom/bluetooth/moz.build b/dom/bluetooth/moz.build
index 6527f4bfdb7..0da9c0af22d 100644
--- a/dom/bluetooth/moz.build
+++ b/dom/bluetooth/moz.build
@@ -73,3 +73,6 @@ IPDL_SOURCES += [
     'ipc/PBluetooth.ipdl',
     'ipc/PBluetoothRequest.ipdl',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/browser-element/Makefile.in b/dom/browser-element/Makefile.in
index 948cfaf2a4b..36f48419a55 100644
--- a/dom/browser-element/Makefile.in
+++ b/dom/browser-element/Makefile.in
@@ -11,8 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME     = dom_browserelement_s
 LIBXUL_LIBRARY   = 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/dom/dom-config.mk
 
 
diff --git a/dom/browser-element/moz.build b/dom/browser-element/moz.build
index f37264ea6c1..b1107a27406 100644
--- a/dom/browser-element/moz.build
+++ b/dom/browser-element/moz.build
@@ -39,3 +39,6 @@ EXTRA_JS_MODULES += [
     'BrowserElementParent.jsm',
     'BrowserElementPromptService.jsm',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/camera/Makefile.in b/dom/camera/Makefile.in
index 85644a29983..9fcbc7d3396 100644
--- a/dom/camera/Makefile.in
+++ b/dom/camera/Makefile.in
@@ -11,8 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME     = domcamera_s
 LIBXUL_LIBRARY   = 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/dom/dom-config.mk
 include $(topsrcdir)/config/rules.mk
 include $(topsrcdir)/ipc/chromium/chromium-config.mk
diff --git a/dom/camera/moz.build b/dom/camera/moz.build
index 92d1b845203..a2b490d0b9c 100644
--- a/dom/camera/moz.build
+++ b/dom/camera/moz.build
@@ -44,3 +44,6 @@ else:
         'FallbackCameraManager.cpp',
         'FallbackCameraControl.cpp',
     ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/cellbroadcast/src/Makefile.in b/dom/cellbroadcast/src/Makefile.in
index 658a2a1fef5..8876a245c95 100644
--- a/dom/cellbroadcast/src/Makefile.in
+++ b/dom/cellbroadcast/src/Makefile.in
@@ -11,8 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME     = dom_cellbroadcast_s
 LIBXUL_LIBRARY   = 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/dom/dom-config.mk
 
 include $(topsrcdir)/config/rules.mk
diff --git a/dom/cellbroadcast/src/moz.build b/dom/cellbroadcast/src/moz.build
index e1b5599978f..66bc823993e 100644
--- a/dom/cellbroadcast/src/moz.build
+++ b/dom/cellbroadcast/src/moz.build
@@ -14,3 +14,5 @@ CPP_SOURCES += [
     'CellBroadcast.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/devicestorage/Makefile.in b/dom/devicestorage/Makefile.in
index 64840219d03..36db62339a7 100644
--- a/dom/devicestorage/Makefile.in
+++ b/dom/devicestorage/Makefile.in
@@ -11,8 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME     = domdevicestorage_s
 LIBXUL_LIBRARY   = 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/dom/dom-config.mk
 
 LOCAL_INCLUDES = \
diff --git a/dom/devicestorage/moz.build b/dom/devicestorage/moz.build
index d2929b4f256..0aa16bd9180 100644
--- a/dom/devicestorage/moz.build
+++ b/dom/devicestorage/moz.build
@@ -29,3 +29,6 @@ CPP_SOURCES += [
 IPDL_SOURCES += [
     'PDeviceStorageRequest.ipdl',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/encoding/Makefile.in b/dom/encoding/Makefile.in
index 742e607c559..3de7da972b1 100644
--- a/dom/encoding/Makefile.in
+++ b/dom/encoding/Makefile.in
@@ -6,8 +6,6 @@ DEPTH		= @DEPTH@
 topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME	= domencoding_s
diff --git a/dom/encoding/moz.build b/dom/encoding/moz.build
index 81fb2eb00d0..611fa44de81 100644
--- a/dom/encoding/moz.build
+++ b/dom/encoding/moz.build
@@ -22,3 +22,5 @@ CPP_SOURCES += [
     'TextEncoder.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/file/Makefile.in b/dom/file/Makefile.in
index 2e7f112a29b..094bd56b128 100644
--- a/dom/file/Makefile.in
+++ b/dom/file/Makefile.in
@@ -11,8 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME     = domfile_s
 LIBXUL_LIBRARY   = 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/dom/dom-config.mk
 
 include $(topsrcdir)/config/rules.mk
diff --git a/dom/file/moz.build b/dom/file/moz.build
index 1f96114fee2..330534a1c40 100644
--- a/dom/file/moz.build
+++ b/dom/file/moz.build
@@ -55,3 +55,5 @@ CPP_SOURCES += [
     'MetadataHelper.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/gamepad/Makefile.in b/dom/gamepad/Makefile.in
index f29e3bee659..3bcc4cc0905 100644
--- a/dom/gamepad/Makefile.in
+++ b/dom/gamepad/Makefile.in
@@ -11,8 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME    = domgamepad_s
 LIBXUL_LIBRARY  = 1
-FAIL_ON_WARNINGS := 1
-
 LOCAL_INCLUDES += \
   -I$(topsrcdir)/dom/base \
   $(NULL)
diff --git a/dom/gamepad/moz.build b/dom/gamepad/moz.build
index d9fdac941c9..41e2a4e51af 100644
--- a/dom/gamepad/moz.build
+++ b/dom/gamepad/moz.build
@@ -13,3 +13,6 @@ CPP_SOURCES = [
     'Gamepad.cpp',
     'GamepadService.cpp',
     ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/icc/src/Makefile.in b/dom/icc/src/Makefile.in
index 53bb76a9f17..b87e52d9ac3 100644
--- a/dom/icc/src/Makefile.in
+++ b/dom/icc/src/Makefile.in
@@ -11,8 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME     = dom_icc_s
 LIBXUL_LIBRARY   = 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/dom/dom-config.mk
 
 LOCAL_INCLUDES = \
diff --git a/dom/icc/src/moz.build b/dom/icc/src/moz.build
index e5e527fd48c..151f6fdd028 100644
--- a/dom/icc/src/moz.build
+++ b/dom/icc/src/moz.build
@@ -13,3 +13,5 @@ CPP_SOURCES += [
     'StkCommandEvent.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/indexedDB/Makefile.in b/dom/indexedDB/Makefile.in
index fcbe4ad23f7..0eb1a52894d 100644
--- a/dom/indexedDB/Makefile.in
+++ b/dom/indexedDB/Makefile.in
@@ -11,8 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME = dom_indexeddb_s
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS := 1
-
 LOCAL_INCLUDES = \
   -I$(topsrcdir)/caps/include \
   -I$(topsrcdir)/content/base/src \
diff --git a/dom/indexedDB/ipc/Makefile.in b/dom/indexedDB/ipc/Makefile.in
index 1bacc1f590a..2703e9afc12 100644
--- a/dom/indexedDB/ipc/Makefile.in
+++ b/dom/indexedDB/ipc/Makefile.in
@@ -7,8 +7,6 @@ topsrcdir = @top_srcdir@
 srcdir = @srcdir@
 relativesrcdir = @relativesrcdir@
 VPATH = @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME = dom_indexeddb_ipc_s
diff --git a/dom/indexedDB/ipc/moz.build b/dom/indexedDB/ipc/moz.build
index f271ec09f04..635910d91ad 100644
--- a/dom/indexedDB/ipc/moz.build
+++ b/dom/indexedDB/ipc/moz.build
@@ -29,3 +29,6 @@ IPDL_SOURCES += [
     'PIndexedDBRequest.ipdl',
     'PIndexedDBTransaction.ipdl',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/indexedDB/moz.build b/dom/indexedDB/moz.build
index 679b08068d6..4f026c94232 100644
--- a/dom/indexedDB/moz.build
+++ b/dom/indexedDB/moz.build
@@ -63,3 +63,5 @@ CPP_SOURCES += [
     'TransactionThreadPool.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/ipc/Makefile.in b/dom/ipc/Makefile.in
index 32942fb54fa..55535347622 100644
--- a/dom/ipc/Makefile.in
+++ b/dom/ipc/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME = domipc_s
 LIBXUL_LIBRARY = 1
 EXPORT_LIBRARY = 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/config/rules.mk
 include $(topsrcdir)/ipc/chromium/chromium-config.mk
 
diff --git a/dom/ipc/moz.build b/dom/ipc/moz.build
index 5bfbd1722fd..b55c9588dba 100644
--- a/dom/ipc/moz.build
+++ b/dom/ipc/moz.build
@@ -70,3 +70,6 @@ IPDL_SOURCES += [
     'PMemoryReportRequest.ipdl',
     'PTabContext.ipdlh',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/media/Makefile.in b/dom/media/Makefile.in
index a9142703acf..a35ae6a06b3 100644
--- a/dom/media/Makefile.in
+++ b/dom/media/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME     = dom_media_s
 LIBXUL_LIBRARY   = 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/dom/dom-config.mk
 
 
diff --git a/dom/media/moz.build b/dom/media/moz.build
index a71a2e08e88..19c1ed8d6fa 100644
--- a/dom/media/moz.build
+++ b/dom/media/moz.build
@@ -31,3 +31,6 @@ EXTRA_COMPONENTS += [
     'PeerConnection.js',
     'PeerConnection.manifest',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/mobilemessage/src/Makefile.in b/dom/mobilemessage/src/Makefile.in
index 07be2a66111..81fcd515b1c 100644
--- a/dom/mobilemessage/src/Makefile.in
+++ b/dom/mobilemessage/src/Makefile.in
@@ -23,8 +23,6 @@ endif
 LIBRARY_NAME     = dom_mobilemessage_s
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY   = 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/dom/dom-config.mk
 
 LOCAL_INCLUDES = \
diff --git a/dom/mobilemessage/src/moz.build b/dom/mobilemessage/src/moz.build
index 0d37deba1a6..eaa7afc78b5 100644
--- a/dom/mobilemessage/src/moz.build
+++ b/dom/mobilemessage/src/moz.build
@@ -78,3 +78,6 @@ IPDL_SOURCES += [
     'ipc/PSmsRequest.ipdl',
     'ipc/SmsTypes.ipdlh',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/network/src/Makefile.in b/dom/network/src/Makefile.in
index d7232a698f7..43edada4d91 100644
--- a/dom/network/src/Makefile.in
+++ b/dom/network/src/Makefile.in
@@ -11,9 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME     = dom_network_s
 LIBXUL_LIBRARY   = 1
-FAIL_ON_WARNINGS := 1
-
-
 ifdef MOZ_B2G_RIL
 endif
 
diff --git a/dom/network/src/moz.build b/dom/network/src/moz.build
index 840c6cac257..9cd72ee2790 100644
--- a/dom/network/src/moz.build
+++ b/dom/network/src/moz.build
@@ -47,3 +47,6 @@ IPDL_SOURCES += [
     'PTCPServerSocket.ipdl',
     'PTCPSocket.ipdl',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/plugins/base/Makefile.in b/dom/plugins/base/Makefile.in
index 32478221476..297d4dc3eab 100644
--- a/dom/plugins/base/Makefile.in
+++ b/dom/plugins/base/Makefile.in
@@ -17,11 +17,6 @@ LIBXUL_LIBRARY = 1
 
 ifeq ($(MOZ_WIDGET_TOOLKIT),android)
 LOCAL_INCLUDES += -I$(topsrcdir)/dom/plugins/base/android
-else
-# android_npapi.h extends the NPNVariable and NPPVariable enums
-# using #defines, which results in Wswitch warnings in gcc-4.6.
-# Therefore, enable FAIL_ON_WARNINGS only on non-Android platforms.
-FAIL_ON_WARNINGS := 1
 endif
 
 ifeq ($(OS_ARCH),WINNT)
diff --git a/dom/plugins/base/android/Makefile.in b/dom/plugins/base/android/Makefile.in
index 4af352a492f..06619495f91 100644
--- a/dom/plugins/base/android/Makefile.in
+++ b/dom/plugins/base/android/Makefile.in
@@ -13,8 +13,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME	= gkpluginandroid_s
 LIBXUL_LIBRARY   = 1
 EXPORT_LIBRARY = 1
-FAIL_ON_WARNINGS := 1
-
 LOCAL_INCLUDES += \
   -I$(topsrcdir)/widget/android \
   -I$(topsrcdir)/widget/xpwidgets \
diff --git a/dom/plugins/base/android/moz.build b/dom/plugins/base/android/moz.build
index 9dc96cdb1a9..e5f0cb78e47 100644
--- a/dom/plugins/base/android/moz.build
+++ b/dom/plugins/base/android/moz.build
@@ -25,3 +25,5 @@ CPP_SOURCES += [
     'ANPWindow.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/plugins/base/moz.build b/dom/plugins/base/moz.build
index 7b11cde4a99..bbc2be278aa 100644
--- a/dom/plugins/base/moz.build
+++ b/dom/plugins/base/moz.build
@@ -88,3 +88,9 @@ else:
         CPP_SOURCES += [
             'nsPluginNativeWindow.cpp',
         ]
+
+if CONFIG['MOZ_WIDGET_TOOLKIT'] != 'android':
+    # android_npapi.h extends the NPNVariable and NPPVariable enums
+    # using #defines, which results in Wswitch warnings in gcc-4.6.
+    # Therefore, enable FAIL_ON_WARNINGS only on non-Android platforms.
+    FAIL_ON_WARNINGS = True
diff --git a/dom/plugins/ipc/Makefile.in b/dom/plugins/ipc/Makefile.in
index c5beb773318..27a0000a88a 100644
--- a/dom/plugins/ipc/Makefile.in
+++ b/dom/plugins/ipc/Makefile.in
@@ -9,8 +9,6 @@ VPATH = @srcdir@
 
 include $(DEPTH)/config/autoconf.mk
 
-FAIL_ON_WARNINGS := 1
-
 LIBRARY_NAME     = domplugins_s
 LIBXUL_LIBRARY   = 1
 EXPORT_LIBRARY = 1
diff --git a/dom/plugins/ipc/moz.build b/dom/plugins/ipc/moz.build
index d3e14784248..9242aeb3802 100644
--- a/dom/plugins/ipc/moz.build
+++ b/dom/plugins/ipc/moz.build
@@ -102,3 +102,6 @@ IPDL_SOURCES += [
     'PPluginSurface.ipdl',
     'PStreamNotify.ipdl',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/plugins/test/testplugin/Makefile.in b/dom/plugins/test/testplugin/Makefile.in
index 85fa7c27e6c..19a08ec3986 100644
--- a/dom/plugins/test/testplugin/Makefile.in
+++ b/dom/plugins/test/testplugin/Makefile.in
@@ -11,9 +11,6 @@ VPATH     = @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 MODULE_NAME  = TestPlugin
-ifndef _MSC_VER
-FAIL_ON_WARNINGS = 1
-endif # !_MSC_VER
 
 RELATIVE_PATH=.
 COCOA_NAME=Test
diff --git a/dom/plugins/test/testplugin/moz.build b/dom/plugins/test/testplugin/moz.build
index 2d1944ebc55..4d1c1b0d8c8 100644
--- a/dom/plugins/test/testplugin/moz.build
+++ b/dom/plugins/test/testplugin/moz.build
@@ -11,3 +11,4 @@ NO_DIST_INSTALL = True
 
 LIBRARY_NAME = 'nptest'
 
+FAIL_ON_WARNINGS = not CONFIG['_MSC_VER']
diff --git a/dom/power/Makefile.in b/dom/power/Makefile.in
index ea4da2c1e7b..67c50e2f4af 100644
--- a/dom/power/Makefile.in
+++ b/dom/power/Makefile.in
@@ -11,8 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME     = dom_power_s
 LIBXUL_LIBRARY   = 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/dom/dom-config.mk
 
 include $(topsrcdir)/config/rules.mk
diff --git a/dom/power/moz.build b/dom/power/moz.build
index a4d35f36dce..8ea0bba66ef 100644
--- a/dom/power/moz.build
+++ b/dom/power/moz.build
@@ -27,3 +27,5 @@ CPP_SOURCES += [
     'WakeLock.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/promise/Makefile.in b/dom/promise/Makefile.in
index 18cb01cb2fb..53a4599f3e1 100644
--- a/dom/promise/Makefile.in
+++ b/dom/promise/Makefile.in
@@ -11,8 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME     = dompromise_s
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS := 1
-
 LOCAL_INCLUDES += \
   -I$(topsrcdir)/dom/workers \
   -I$(topsrcdir)/dom/base \
diff --git a/dom/promise/moz.build b/dom/promise/moz.build
index e3074a1360d..160121e1c36 100644
--- a/dom/promise/moz.build
+++ b/dom/promise/moz.build
@@ -20,3 +20,6 @@ CPP_SOURCES += [
     'PromiseResolver.cpp',
     'PromiseCallback.cpp',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/quota/Makefile.in b/dom/quota/Makefile.in
index 5d07fab274c..d5ae9c16ef4 100644
--- a/dom/quota/Makefile.in
+++ b/dom/quota/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME     = domquota_s
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY   = 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/dom/dom-config.mk
 
 LOCAL_INCLUDES = \
diff --git a/dom/quota/moz.build b/dom/quota/moz.build
index 5576884cd00..0b68fce2450 100644
--- a/dom/quota/moz.build
+++ b/dom/quota/moz.build
@@ -39,3 +39,5 @@ CPP_SOURCES += [
     'QuotaObject.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/src/events/Makefile.in b/dom/src/events/Makefile.in
index de36ee863ec..bf189dfd465 100644
--- a/dom/src/events/Makefile.in
+++ b/dom/src/events/Makefile.in
@@ -7,8 +7,6 @@ DEPTH		= @DEPTH@
 topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 MSVC_ENABLE_PGO := 1
diff --git a/dom/src/events/moz.build b/dom/src/events/moz.build
index 7d4540410a0..e046d2168cd 100644
--- a/dom/src/events/moz.build
+++ b/dom/src/events/moz.build
@@ -12,3 +12,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'jsdomevents_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/src/geolocation/Makefile.in b/dom/src/geolocation/Makefile.in
index af1ca2a3a50..63520c4ab47 100644
--- a/dom/src/geolocation/Makefile.in
+++ b/dom/src/geolocation/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME   = jsdomgeolocation_s
 LIBXUL_LIBRARY = 1
 
-FAIL_ON_WARNINGS := 1
-
 LOCAL_INCLUDES = \
 		-I$(topsrcdir)/dom/base \
 		-I$(topsrcdir)/dom/ipc \
diff --git a/dom/src/geolocation/moz.build b/dom/src/geolocation/moz.build
index c70f2a089a9..17867530af1 100644
--- a/dom/src/geolocation/moz.build
+++ b/dom/src/geolocation/moz.build
@@ -16,3 +16,5 @@ CPP_SOURCES += [
     'nsGeolocation.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/src/json/Makefile.in b/dom/src/json/Makefile.in
index b8d2e9ab8df..bc72b003374 100644
--- a/dom/src/json/Makefile.in
+++ b/dom/src/json/Makefile.in
@@ -7,8 +7,6 @@ DEPTH          = @DEPTH@
 topsrcdir      = @top_srcdir@
 srcdir         = @srcdir@
 VPATH          = @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
diff --git a/dom/src/json/moz.build b/dom/src/json/moz.build
index 43e24ae4f10..cf5c434400a 100644
--- a/dom/src/json/moz.build
+++ b/dom/src/json/moz.build
@@ -18,3 +18,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'json_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/src/jsurl/Makefile.in b/dom/src/jsurl/Makefile.in
index 28770ed69b3..f5998d025a7 100644
--- a/dom/src/jsurl/Makefile.in
+++ b/dom/src/jsurl/Makefile.in
@@ -7,8 +7,6 @@ DEPTH		= @DEPTH@
 topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY	= 1
diff --git a/dom/src/jsurl/moz.build b/dom/src/jsurl/moz.build
index a2830d7dc9b..14e764ec93d 100644
--- a/dom/src/jsurl/moz.build
+++ b/dom/src/jsurl/moz.build
@@ -18,3 +18,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'jsurl_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/src/notification/Makefile.in b/dom/src/notification/Makefile.in
index 435a4a67327..003c474164e 100644
--- a/dom/src/notification/Makefile.in
+++ b/dom/src/notification/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME   = jsdomnotification_s
 LIBXUL_LIBRARY = 1
 
-FAIL_ON_WARNINGS := 1
-
 LOCAL_INCLUDES = \
   -I$(topsrcdir)/dom/base \
   -I$(topsrcdir)/dom/ipc \
diff --git a/dom/src/notification/moz.build b/dom/src/notification/moz.build
index 1819dcc0f1e..e15e448bf80 100644
--- a/dom/src/notification/moz.build
+++ b/dom/src/notification/moz.build
@@ -16,3 +16,5 @@ CPP_SOURCES += [
     'Notification.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/src/offline/Makefile.in b/dom/src/offline/Makefile.in
index 1dea9680236..1db97b570c3 100644
--- a/dom/src/offline/Makefile.in
+++ b/dom/src/offline/Makefile.in
@@ -11,8 +11,6 @@ VPATH          = @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS := 1
-
 LOCAL_INCLUDES = \
 		-I$(topsrcdir)/dom/base \
 		-I$(topsrcdir)/content/base/src \
diff --git a/dom/src/offline/moz.build b/dom/src/offline/moz.build
index 0f8667fcbd1..0bdb1402e25 100644
--- a/dom/src/offline/moz.build
+++ b/dom/src/offline/moz.build
@@ -15,3 +15,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'jsdomoffline_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/src/storage/Makefile.in b/dom/src/storage/Makefile.in
index 2aa49de4a8f..fc524ee4100 100644
--- a/dom/src/storage/Makefile.in
+++ b/dom/src/storage/Makefile.in
@@ -7,8 +7,6 @@ DEPTH          = @DEPTH@
 topsrcdir      = @top_srcdir@
 srcdir         = @srcdir@
 VPATH          = @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME   = jsdomstorage_s
diff --git a/dom/src/storage/moz.build b/dom/src/storage/moz.build
index 8eaf17b1bc8..942d85c5517 100644
--- a/dom/src/storage/moz.build
+++ b/dom/src/storage/moz.build
@@ -22,3 +22,6 @@ CPP_SOURCES += [
 IPDL_SOURCES += [
     'PStorage.ipdl',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/system/Makefile.in b/dom/system/Makefile.in
index 092cfa2ecd8..738667ac394 100644
--- a/dom/system/Makefile.in
+++ b/dom/system/Makefile.in
@@ -11,8 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME    = domsystem_s
 LIBXUL_LIBRARY  = 1
-FAIL_ON_WARNINGS := 1
-
 DEFINES += -DDLL_PREFIX=\"$(DLL_PREFIX)\" -DDLL_SUFFIX=\"$(DLL_SUFFIX)\"
 
 # We fire the nsDOMDeviceAcceleration
diff --git a/dom/system/android/Makefile.in b/dom/system/android/Makefile.in
index 70991e44d9b..9c273aeed62 100644
--- a/dom/system/android/Makefile.in
+++ b/dom/system/android/Makefile.in
@@ -13,8 +13,6 @@ LIBRARY_NAME    = domsystemandroid_s
 
 LIBXUL_LIBRARY   = 1
 EXPORT_LIBRARY = 1
-FAIL_ON_WARNINGS := 1
-
 LOCAL_INCLUDES  += -I$(topsrcdir)/dom/src/geolocation \
                      -I$(topsrcdir)/content/events/src
                      $(NULL)
diff --git a/dom/system/android/moz.build b/dom/system/android/moz.build
index b8150629540..94f68e67680 100644
--- a/dom/system/android/moz.build
+++ b/dom/system/android/moz.build
@@ -11,3 +11,5 @@ CPP_SOURCES += [
     'nsHapticFeedback.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/system/gonk/Makefile.in b/dom/system/gonk/Makefile.in
index 1693886bf6c..322944de51f 100644
--- a/dom/system/gonk/Makefile.in
+++ b/dom/system/gonk/Makefile.in
@@ -23,8 +23,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME     = domsystemgonk_s
 LIBXUL_LIBRARY   = 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/dom/dom-config.mk
 
 LOCAL_INCLUDES = \
diff --git a/dom/system/gonk/moz.build b/dom/system/gonk/moz.build
index 8b2558aa6f5..777bde46117 100644
--- a/dom/system/gonk/moz.build
+++ b/dom/system/gonk/moz.build
@@ -80,3 +80,5 @@ EXTRA_JS_MODULES += [
     'systemlibs.js',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/system/mac/Makefile.in b/dom/system/mac/Makefile.in
index 1a625657221..77be2743906 100644
--- a/dom/system/mac/Makefile.in
+++ b/dom/system/mac/Makefile.in
@@ -13,8 +13,6 @@ LIBRARY_NAME    = domsystemmac_s
 
 LIBXUL_LIBRARY   = 1
 EXPORT_LIBRARY = 1
-FAIL_ON_WARNINGS := 1
-
 LOCAL_INCLUDES  += -I$(topsrcdir)/dom/src/geolocation \
                    $(NULL)
 
diff --git a/dom/system/mac/moz.build b/dom/system/mac/moz.build
index 33ceee8b74a..417ce5b25c5 100644
--- a/dom/system/mac/moz.build
+++ b/dom/system/mac/moz.build
@@ -7,3 +7,6 @@
 MODULE = 'dom'
 
 CMMSRCS += ['CoreLocationLocationProvider.mm']
+
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/system/moz.build b/dom/system/moz.build
index 8762019ef46..5948c80c303 100644
--- a/dom/system/moz.build
+++ b/dom/system/moz.build
@@ -49,3 +49,5 @@ if CONFIG['OS_TARGET'] != 'Android' or CONFIG['MOZ_WIDGET_TOOLKIT'] == 'gonk':
         'NetworkGeolocationProvider.manifest',
     ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/system/unix/Makefile.in b/dom/system/unix/Makefile.in
index 704e52339e2..a15832e31d0 100644
--- a/dom/system/unix/Makefile.in
+++ b/dom/system/unix/Makefile.in
@@ -13,8 +13,6 @@ LIBRARY_NAME    = domsystemunix_s
 
 LIBXUL_LIBRARY   = 1
 EXPORT_LIBRARY = 1
-FAIL_ON_WARNINGS := 1
-
 ifdef MOZ_MAEMO_LIBLOCATION
         LOCAL_INCLUDES  += $(MOZ_PLATFORM_MAEMO_CFLAGS) \
                            -I$(topsrcdir)/dom/src/geolocation \
diff --git a/dom/system/unix/moz.build b/dom/system/unix/moz.build
index 297dd5a46f2..cf8e10bda1b 100644
--- a/dom/system/unix/moz.build
+++ b/dom/system/unix/moz.build
@@ -21,3 +21,6 @@ if CONFIG['MOZ_ENABLE_QTMOBILITY']:
         'moc_QTMLocationProvider.cpp',
         'QTMLocationProvider.cpp',
     ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/system/windows/Makefile.in b/dom/system/windows/Makefile.in
index e0e706bc048..71dea5cbbff 100644
--- a/dom/system/windows/Makefile.in
+++ b/dom/system/windows/Makefile.in
@@ -13,7 +13,6 @@ LIBRARY_NAME    = domsystemwindows_s
 
 LIBXUL_LIBRARY   = 1
 EXPORT_LIBRARY = 1
-FAIL_ON_WARNINGS := 1
 
 # We fire the nsDOMDeviceAcceleration
 LOCAL_INCLUDES += -I$(topsrcdir)/content/events/src
diff --git a/dom/system/windows/moz.build b/dom/system/windows/moz.build
index 7da139c862b..03a01af6ef2 100644
--- a/dom/system/windows/moz.build
+++ b/dom/system/windows/moz.build
@@ -10,3 +10,5 @@ CPP_SOURCES += [
     'nsHapticFeedback.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/telephony/Makefile.in b/dom/telephony/Makefile.in
index 7b47c9360ae..6753f22bfa2 100644
--- a/dom/telephony/Makefile.in
+++ b/dom/telephony/Makefile.in
@@ -11,8 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME     = domtelephony_s
 LIBXUL_LIBRARY   = 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/dom/dom-config.mk
 
 include $(topsrcdir)/config/rules.mk
diff --git a/dom/telephony/moz.build b/dom/telephony/moz.build
index 35d757c71b0..2be5c7040ee 100644
--- a/dom/telephony/moz.build
+++ b/dom/telephony/moz.build
@@ -20,3 +20,5 @@ CPP_SOURCES += [
     'TelephonyCallGroup.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/time/Makefile.in b/dom/time/Makefile.in
index d5f5d6f34f3..5d0c34c2c41 100644
--- a/dom/time/Makefile.in
+++ b/dom/time/Makefile.in
@@ -11,8 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME     = dom_time_s
 LIBXUL_LIBRARY   = 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/dom/dom-config.mk
 
 include $(topsrcdir)/config/rules.mk
diff --git a/dom/time/moz.build b/dom/time/moz.build
index 74cde53b8ba..58433801702 100644
--- a/dom/time/moz.build
+++ b/dom/time/moz.build
@@ -26,3 +26,5 @@ CPP_SOURCES += [
     'TimeService.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/voicemail/Makefile.in b/dom/voicemail/Makefile.in
index 5da1f55de22..cc0051de836 100644
--- a/dom/voicemail/Makefile.in
+++ b/dom/voicemail/Makefile.in
@@ -11,8 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME     = domvoicemail_s
 LIBXUL_LIBRARY   = 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/dom/dom-config.mk
 
 include $(topsrcdir)/config/rules.mk
diff --git a/dom/voicemail/moz.build b/dom/voicemail/moz.build
index 5d7511145f1..7fbb017f7fa 100644
--- a/dom/voicemail/moz.build
+++ b/dom/voicemail/moz.build
@@ -23,3 +23,5 @@ CPP_SOURCES += [
     'Voicemail.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/dom/workers/Makefile.in b/dom/workers/Makefile.in
index 9e901ac69a9..70dc38ad76c 100644
--- a/dom/workers/Makefile.in
+++ b/dom/workers/Makefile.in
@@ -11,8 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY   = 1
-FAIL_ON_WARNINGS := 1
-
 LOCAL_INCLUDES = \
   -I$(topsrcdir)/content/base/src \
   -I$(topsrcdir)/content/events/src \
diff --git a/dom/workers/moz.build b/dom/workers/moz.build
index c5834d722a9..e6f4ab5e858 100644
--- a/dom/workers/moz.build
+++ b/dom/workers/moz.build
@@ -57,3 +57,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'domworkers_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/editor/Makefile.in b/editor/Makefile.in
deleted file mode 100644
index 5f45bab6fa0..00000000000
--- a/editor/Makefile.in
+++ /dev/null
@@ -1,15 +0,0 @@
-#
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-DEPTH            := @DEPTH@
-topsrcdir        := @top_srcdir@
-srcdir           := @srcdir@
-VPATH            := @srcdir@
-FAIL_ON_WARNINGS := 1
-
-include $(DEPTH)/config/autoconf.mk
-
-include $(topsrcdir)/config/rules.mk
-
diff --git a/editor/composer/src/Makefile.in b/editor/composer/src/Makefile.in
index 77751366944..f41d5d9878b 100644
--- a/editor/composer/src/Makefile.in
+++ b/editor/composer/src/Makefile.in
@@ -12,9 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 EXPORT_LIBRARY = 1
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
-
 include $(topsrcdir)/config/rules.mk
 
 INCLUDES        += \
diff --git a/editor/composer/src/moz.build b/editor/composer/src/moz.build
index 8dc94a15a34..2443ef42d71 100644
--- a/editor/composer/src/moz.build
+++ b/editor/composer/src/moz.build
@@ -19,3 +19,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'composer'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/editor/libeditor/base/Makefile.in b/editor/libeditor/base/Makefile.in
index 743a9d36e43..282f769c07f 100644
--- a/editor/libeditor/base/Makefile.in
+++ b/editor/libeditor/base/Makefile.in
@@ -11,8 +11,6 @@ VPATH		= @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 
 # Internal header files, needed by other editor sublibs:
 INTERNAL_HDR_DIR = ../internal
diff --git a/editor/libeditor/base/moz.build b/editor/libeditor/base/moz.build
index 44780caac07..afc0f344ec3 100644
--- a/editor/libeditor/base/moz.build
+++ b/editor/libeditor/base/moz.build
@@ -35,3 +35,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'editorbase_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/editor/libeditor/html/Makefile.in b/editor/libeditor/html/Makefile.in
index 8e1523d3f44..0037b3268f9 100644
--- a/editor/libeditor/html/Makefile.in
+++ b/editor/libeditor/html/Makefile.in
@@ -7,8 +7,6 @@ DEPTH		= @DEPTH@
 topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
-FAIL_ON_WARNINGS = 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY	= 1
diff --git a/editor/libeditor/html/moz.build b/editor/libeditor/html/moz.build
index 696625d6879..5aa17c00e76 100644
--- a/editor/libeditor/html/moz.build
+++ b/editor/libeditor/html/moz.build
@@ -30,3 +30,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'htmleditor_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/editor/libeditor/text/Makefile.in b/editor/libeditor/text/Makefile.in
index abf29f57fbc..66d795ff40b 100644
--- a/editor/libeditor/text/Makefile.in
+++ b/editor/libeditor/text/Makefile.in
@@ -7,8 +7,6 @@ DEPTH		= @DEPTH@
 topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
-FAIL_ON_WARNINGS = 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY	= 1
diff --git a/editor/libeditor/text/moz.build b/editor/libeditor/text/moz.build
index 2ea07128d6b..4b486a5a7cb 100644
--- a/editor/libeditor/text/moz.build
+++ b/editor/libeditor/text/moz.build
@@ -19,3 +19,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'texteditor_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/editor/moz.build b/editor/moz.build
index 9aea7eb43b0..36317d53818 100644
--- a/editor/moz.build
+++ b/editor/moz.build
@@ -18,3 +18,6 @@ MODULE = 'editor'
 EXTRA_JS_MODULES += [
     'AsyncSpellCheckTestHelper.jsm',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/editor/txmgr/src/Makefile.in b/editor/txmgr/src/Makefile.in
index 5562ce28253..a321f55e436 100644
--- a/editor/txmgr/src/Makefile.in
+++ b/editor/txmgr/src/Makefile.in
@@ -7,8 +7,6 @@ DEPTH		= @DEPTH@
 topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
-FAIL_ON_WARNINGS = 1
-
 include $(DEPTH)/config/autoconf.mk
 
 EXPORT_LIBRARY = 1
diff --git a/editor/txmgr/src/moz.build b/editor/txmgr/src/moz.build
index 747e4449300..e4c2c638346 100644
--- a/editor/txmgr/src/moz.build
+++ b/editor/txmgr/src/moz.build
@@ -16,3 +16,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'txmgr'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/editor/txmgr/tests/Makefile.in b/editor/txmgr/tests/Makefile.in
deleted file mode 100644
index dcdbd0d6102..00000000000
--- a/editor/txmgr/tests/Makefile.in
+++ /dev/null
@@ -1,15 +0,0 @@
-#
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-DEPTH		= @DEPTH@
-topsrcdir	= @top_srcdir@
-srcdir		= @srcdir@
-VPATH		= @srcdir@
-FAIL_ON_WARNINGS = 1
-
-include $(DEPTH)/config/autoconf.mk
-
-
-include $(topsrcdir)/config/rules.mk
diff --git a/editor/txmgr/tests/moz.build b/editor/txmgr/tests/moz.build
index 727b18a4f49..a764ecda81d 100644
--- a/editor/txmgr/tests/moz.build
+++ b/editor/txmgr/tests/moz.build
@@ -8,3 +8,5 @@ CPP_UNIT_TESTS += [
     'TestTXMgr.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/editor/txtsvc/src/Makefile.in b/editor/txtsvc/src/Makefile.in
index 58dd5e52834..fd85f0e763b 100644
--- a/editor/txtsvc/src/Makefile.in
+++ b/editor/txtsvc/src/Makefile.in
@@ -7,8 +7,6 @@ DEPTH		= @DEPTH@
 topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
-FAIL_ON_WARNINGS = 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY	= 1
diff --git a/editor/txtsvc/src/moz.build b/editor/txtsvc/src/moz.build
index 4a6d2c402ec..5ba96bbdcb1 100644
--- a/editor/txtsvc/src/moz.build
+++ b/editor/txtsvc/src/moz.build
@@ -13,3 +13,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'txtsvc_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/embedding/browser/build/Makefile.in b/embedding/browser/build/Makefile.in
index 8afb7cdec07..49971524f00 100644
--- a/embedding/browser/build/Makefile.in
+++ b/embedding/browser/build/Makefile.in
@@ -12,9 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 EXPORT_LIBRARY	= 1
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
-
 SHARED_LIBRARY_LIBS= \
 		../webBrowser/$(LIB_PREFIX)nsWebBrowser_s.$(LIB_SUFFIX) \
 		$(NULL)
diff --git a/embedding/browser/build/moz.build b/embedding/browser/build/moz.build
index f5417fbf670..4cc6164e822 100644
--- a/embedding/browser/build/moz.build
+++ b/embedding/browser/build/moz.build
@@ -12,3 +12,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'webbrwsr'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/embedding/browser/webBrowser/Makefile.in b/embedding/browser/webBrowser/Makefile.in
index c102390464b..5c94410916a 100644
--- a/embedding/browser/webBrowser/Makefile.in
+++ b/embedding/browser/webBrowser/Makefile.in
@@ -11,9 +11,6 @@ VPATH		= @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
-
 LOCAL_INCLUDES	= \
 		-I$(srcdir)/../../../content/base/src \
 		-I$(srcdir)/../../../content/svg/content/src \
diff --git a/embedding/browser/webBrowser/moz.build b/embedding/browser/webBrowser/moz.build
index 3dd0283c25e..5563abcaad9 100644
--- a/embedding/browser/webBrowser/moz.build
+++ b/embedding/browser/webBrowser/moz.build
@@ -48,3 +48,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'nsWebBrowser_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/embedding/components/appstartup/src/Makefile.in b/embedding/components/appstartup/src/Makefile.in
index a688d9264c3..123dfb54523 100644
--- a/embedding/components/appstartup/src/Makefile.in
+++ b/embedding/components/appstartup/src/Makefile.in
@@ -11,7 +11,5 @@ VPATH		= @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
diff --git a/embedding/components/appstartup/src/moz.build b/embedding/components/appstartup/src/moz.build
index a157a9122b4..388155d7faa 100644
--- a/embedding/components/appstartup/src/moz.build
+++ b/embedding/components/appstartup/src/moz.build
@@ -16,3 +16,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'appstartupnotifier_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/embedding/components/build/Makefile.in b/embedding/components/build/Makefile.in
index bac0b55b618..248260521d9 100644
--- a/embedding/components/build/Makefile.in
+++ b/embedding/components/build/Makefile.in
@@ -11,8 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 EXPORT_LIBRARY = 1
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 SHARED_LIBRARY_LIBS = \
 	../windowwatcher/src/$(LIB_PREFIX)windowwatcher_s.$(LIB_SUFFIX) \
 	../appstartup/src/$(LIB_PREFIX)appstartupnotifier_s.$(LIB_SUFFIX) \
diff --git a/embedding/components/build/moz.build b/embedding/components/build/moz.build
index ff5ff6190e7..b84f5515f5f 100644
--- a/embedding/components/build/moz.build
+++ b/embedding/components/build/moz.build
@@ -12,3 +12,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'embedcomponents'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/embedding/components/commandhandler/src/Makefile.in b/embedding/components/commandhandler/src/Makefile.in
index a688d9264c3..123dfb54523 100644
--- a/embedding/components/commandhandler/src/Makefile.in
+++ b/embedding/components/commandhandler/src/Makefile.in
@@ -11,7 +11,5 @@ VPATH		= @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
diff --git a/embedding/components/commandhandler/src/moz.build b/embedding/components/commandhandler/src/moz.build
index 1d910842671..6c1f1d52ead 100644
--- a/embedding/components/commandhandler/src/moz.build
+++ b/embedding/components/commandhandler/src/moz.build
@@ -16,3 +16,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'commandhandler_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/embedding/components/find/src/Makefile.in b/embedding/components/find/src/Makefile.in
index a688d9264c3..123dfb54523 100644
--- a/embedding/components/find/src/Makefile.in
+++ b/embedding/components/find/src/Makefile.in
@@ -11,7 +11,5 @@ VPATH		= @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
diff --git a/embedding/components/find/src/moz.build b/embedding/components/find/src/moz.build
index 1680d507765..2b77111d5e9 100644
--- a/embedding/components/find/src/moz.build
+++ b/embedding/components/find/src/moz.build
@@ -13,3 +13,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'find_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/embedding/components/printingui/src/mac/Makefile.in b/embedding/components/printingui/src/mac/Makefile.in
index d28673d00ab..d4ecaf565a0 100644
--- a/embedding/components/printingui/src/mac/Makefile.in
+++ b/embedding/components/printingui/src/mac/Makefile.in
@@ -12,10 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 EXPORT_LIBRARY	= ..
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
-
-
 LOCAL_INCLUDES	= \
 		$(NULL)
 
diff --git a/embedding/components/printingui/src/mac/moz.build b/embedding/components/printingui/src/mac/moz.build
index d5e5dcf0ac6..bd971567efa 100644
--- a/embedding/components/printingui/src/mac/moz.build
+++ b/embedding/components/printingui/src/mac/moz.build
@@ -16,3 +16,6 @@ LIBRARY_NAME = 'printingui_s'
 CMMSRCS += [
     'nsPrintingPromptServiceX.mm',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/embedding/components/printingui/src/unixshared/Makefile.in b/embedding/components/printingui/src/unixshared/Makefile.in
index 766378c7d0a..1fb1c328950 100644
--- a/embedding/components/printingui/src/unixshared/Makefile.in
+++ b/embedding/components/printingui/src/unixshared/Makefile.in
@@ -12,7 +12,5 @@ include $(DEPTH)/config/autoconf.mk
 
 EXPORT_LIBRARY	= ..
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
diff --git a/embedding/components/printingui/src/unixshared/moz.build b/embedding/components/printingui/src/unixshared/moz.build
index e1747e7c85f..04982c860cd 100644
--- a/embedding/components/printingui/src/unixshared/moz.build
+++ b/embedding/components/printingui/src/unixshared/moz.build
@@ -14,3 +14,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'printingui_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/embedding/components/printingui/src/win/Makefile.in b/embedding/components/printingui/src/win/Makefile.in
index 766378c7d0a..1fb1c328950 100644
--- a/embedding/components/printingui/src/win/Makefile.in
+++ b/embedding/components/printingui/src/win/Makefile.in
@@ -12,7 +12,5 @@ include $(DEPTH)/config/autoconf.mk
 
 EXPORT_LIBRARY	= ..
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
diff --git a/embedding/components/printingui/src/win/moz.build b/embedding/components/printingui/src/win/moz.build
index cabf41dd747..9e108f31a6b 100644
--- a/embedding/components/printingui/src/win/moz.build
+++ b/embedding/components/printingui/src/win/moz.build
@@ -15,3 +15,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'printingui_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/embedding/components/webbrowserpersist/src/Makefile.in b/embedding/components/webbrowserpersist/src/Makefile.in
index e82ebf0086b..6297c32482b 100644
--- a/embedding/components/webbrowserpersist/src/Makefile.in
+++ b/embedding/components/webbrowserpersist/src/Makefile.in
@@ -11,8 +11,6 @@ VPATH		= @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
 LOCAL_INCLUDES	= \
diff --git a/embedding/components/webbrowserpersist/src/moz.build b/embedding/components/webbrowserpersist/src/moz.build
index 5066372752e..c6ebf92f063 100644
--- a/embedding/components/webbrowserpersist/src/moz.build
+++ b/embedding/components/webbrowserpersist/src/moz.build
@@ -12,3 +12,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'webbrowserpersist_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/embedding/components/windowwatcher/src/Makefile.in b/embedding/components/windowwatcher/src/Makefile.in
index 34e87f5c6e0..ea052094e06 100644
--- a/embedding/components/windowwatcher/src/Makefile.in
+++ b/embedding/components/windowwatcher/src/Makefile.in
@@ -11,9 +11,10 @@ VPATH		= @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
 
 # For nsJSUtils
-LOCAL_INCLUDES += -I$(topsrcdir)/dom/base \
+LOCAL_INCLUDES += \
+  -I$(topsrcdir)/dom/base \
+  $(NULL)
 
 include $(topsrcdir)/config/rules.mk
diff --git a/embedding/components/windowwatcher/src/moz.build b/embedding/components/windowwatcher/src/moz.build
index 452c41e3f2f..f50cf387048 100644
--- a/embedding/components/windowwatcher/src/moz.build
+++ b/embedding/components/windowwatcher/src/moz.build
@@ -18,3 +18,5 @@ if CONFIG['MOZ_XUL']:
 
 LIBRARY_NAME = 'windowwatcher_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/extensions/gio/Makefile.in b/extensions/gio/Makefile.in
index 1fa4e04dd47..8a6f73e6c6d 100644
--- a/extensions/gio/Makefile.in
+++ b/extensions/gio/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 EXPORT_LIBRARY	= 1
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 LOCAL_INCLUDES	= $(MOZ_GIO_CFLAGS)
 
 include $(topsrcdir)/config/rules.mk
diff --git a/extensions/gio/moz.build b/extensions/gio/moz.build
index fc6042030e2..78c2ad97e9b 100644
--- a/extensions/gio/moz.build
+++ b/extensions/gio/moz.build
@@ -12,3 +12,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'nkgio'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/gfx/gl/Makefile.in b/gfx/gl/Makefile.in
index 54a2cd37d1f..c3ad1f792bc 100644
--- a/gfx/gl/Makefile.in
+++ b/gfx/gl/Makefile.in
@@ -13,9 +13,6 @@ LIBRARY_NAME     = gl
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY   = 1
 EXPORT_LIBRARY   = 1
-FAIL_ON_WARNINGS = 1
-
-
 ifeq ($(MOZ_WIDGET_TOOLKIT),windows)
 ifdef MOZ_WEBGL
 DEFINES += -DMOZ_D3DCOMPILER_DLL=$(MOZ_D3DCOMPILER_DLL)
diff --git a/gfx/gl/moz.build b/gfx/gl/moz.build
index 541f60aaed8..e98a6cb6b6f 100644
--- a/gfx/gl/moz.build
+++ b/gfx/gl/moz.build
@@ -116,3 +116,5 @@ CPP_SOURCES += [
     'SurfaceStream.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/gfx/src/Makefile.in b/gfx/src/Makefile.in
index b6881a508c3..bb0d1984cea 100644
--- a/gfx/src/Makefile.in
+++ b/gfx/src/Makefile.in
@@ -13,8 +13,6 @@ include $(DEPTH)/config/autoconf.mk
 MSVC_ENABLE_PGO := 1
 EXPORT_LIBRARY = 1
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
 CXXFLAGS += $(MOZ_CAIRO_CFLAGS) $(MOZ_PIXMAN_CFLAGS) $(TK_CFLAGS)
diff --git a/gfx/src/moz.build b/gfx/src/moz.build
index 3f15bbe78d6..8237e4305be 100644
--- a/gfx/src/moz.build
+++ b/gfx/src/moz.build
@@ -57,3 +57,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'gkgfx'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/gfx/thebes/Makefile.in b/gfx/thebes/Makefile.in
index cb05c10a105..7b9bb8eb6ff 100644
--- a/gfx/thebes/Makefile.in
+++ b/gfx/thebes/Makefile.in
@@ -14,10 +14,6 @@ MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY	= 1
 EXPORT_LIBRARY	= 1
 
-ifndef _MSC_VER
-FAIL_ON_WARNINGS = 1
-endif # !_MSC_VER
-
 # gfxSVGGlyphs needs nsDOMParser.h
 LOCAL_INCLUDES += \
 	-I$(topsrcdir)/content/base/public \
diff --git a/gfx/thebes/moz.build b/gfx/thebes/moz.build
index b855ac9c6d3..85ac6d683fa 100644
--- a/gfx/thebes/moz.build
+++ b/gfx/thebes/moz.build
@@ -268,3 +268,5 @@ if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'cocoa':
     CMMSRCS += [
         'gfxMacPlatformFontList.mm',
     ]
+
+FAIL_ON_WARNINGS = not CONFIG['_MSC_VER']
diff --git a/hal/Makefile.in b/hal/Makefile.in
index f6395f649af..b47a0c72118 100644
--- a/hal/Makefile.in
+++ b/hal/Makefile.in
@@ -24,8 +24,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME   = hal_s
 LIBXUL_LIBRARY = 1
 EXPORT_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 MOCHITEST_BROWSER_FILES += \
 	tests/browser_alarms.js \
 	$(NULL)
diff --git a/hal/moz.build b/hal/moz.build
index f8aaf814534..d8d384072aa 100644
--- a/hal/moz.build
+++ b/hal/moz.build
@@ -149,3 +149,6 @@ if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'cocoa':
 IPDL_SOURCES = [
     'sandbox/PHal.ipdl',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/image/build/Makefile.in b/image/build/Makefile.in
index 14ed56a6f44..290ba3cff95 100644
--- a/image/build/Makefile.in
+++ b/image/build/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 EXPORT_LIBRARY = 1
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 LOCAL_INCLUDES	= \
 		-I. \
 		-I$(srcdir)/../src \
diff --git a/image/build/moz.build b/image/build/moz.build
index a2faeffe95a..4f58423f17b 100644
--- a/image/build/moz.build
+++ b/image/build/moz.build
@@ -12,3 +12,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'imglib2'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/image/decoders/Makefile.in b/image/decoders/Makefile.in
index 8fc0569e1f7..e8ace735d4d 100644
--- a/image/decoders/Makefile.in
+++ b/image/decoders/Makefile.in
@@ -11,8 +11,6 @@ VPATH		= @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY  = 1
-FAIL_ON_WARNINGS = 1
-
 CSRCS   = iccjpeg.c \
           $(NULL)
 
diff --git a/image/decoders/icon/Makefile.in b/image/decoders/icon/Makefile.in
index c8419ae022d..c2fc4ca6e10 100644
--- a/image/decoders/icon/Makefile.in
+++ b/image/decoders/icon/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
 EXPORT_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 ifdef MOZ_WIDGET_GTK
 PLATFORM = gtk
 endif
diff --git a/image/decoders/icon/android/Makefile.in b/image/decoders/icon/android/Makefile.in
index edafdefcdb7..230394f1a8c 100644
--- a/image/decoders/icon/android/Makefile.in
+++ b/image/decoders/icon/android/Makefile.in
@@ -11,7 +11,5 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME	= imgiconandroid_s
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/config/rules.mk
 include $(topsrcdir)/ipc/chromium/chromium-config.mk
diff --git a/image/decoders/icon/android/moz.build b/image/decoders/icon/android/moz.build
index dd14f43309f..217f2a028d0 100644
--- a/image/decoders/icon/android/moz.build
+++ b/image/decoders/icon/android/moz.build
@@ -10,3 +10,5 @@ CPP_SOURCES += [
     'nsIconChannel.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/image/decoders/icon/gtk/Makefile.in b/image/decoders/icon/gtk/Makefile.in
index 4f7f51b91a3..503610e62a7 100644
--- a/image/decoders/icon/gtk/Makefile.in
+++ b/image/decoders/icon/gtk/Makefile.in
@@ -11,8 +11,6 @@ VPATH		= @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY  = 1
-FAIL_ON_WARNINGS = 1
-
 ifdef MOZ_ENABLE_GNOMEUI
 LOCAL_INCLUDES += $(MOZ_GNOMEUI_CFLAGS)
 else
diff --git a/image/decoders/icon/gtk/moz.build b/image/decoders/icon/gtk/moz.build
index 0cb7aa9235f..7c817290a0a 100644
--- a/image/decoders/icon/gtk/moz.build
+++ b/image/decoders/icon/gtk/moz.build
@@ -12,3 +12,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'imgicongtk_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/image/decoders/icon/mac/Makefile.in b/image/decoders/icon/mac/Makefile.in
index 9eaddda84d7..5656cfbb757 100644
--- a/image/decoders/icon/mac/Makefile.in
+++ b/image/decoders/icon/mac/Makefile.in
@@ -10,8 +10,4 @@ VPATH		= @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
-
-
 include $(topsrcdir)/config/rules.mk
diff --git a/image/decoders/icon/mac/moz.build b/image/decoders/icon/mac/moz.build
index 5ad34c100ef..6669f435463 100644
--- a/image/decoders/icon/mac/moz.build
+++ b/image/decoders/icon/mac/moz.build
@@ -11,3 +11,6 @@ LIBRARY_NAME = 'imgiconmac_s'
 CMMSRCS += [
     'nsIconChannelCocoa.mm',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/image/decoders/icon/moz.build b/image/decoders/icon/moz.build
index 68f3a40cfea..649473897aa 100644
--- a/image/decoders/icon/moz.build
+++ b/image/decoders/icon/moz.build
@@ -18,3 +18,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'imgicon'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/image/decoders/icon/win/Makefile.in b/image/decoders/icon/win/Makefile.in
index 8dc0a33fdd0..a819b1fdcba 100644
--- a/image/decoders/icon/win/Makefile.in
+++ b/image/decoders/icon/win/Makefile.in
@@ -11,7 +11,5 @@ VPATH		= @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
diff --git a/image/decoders/icon/win/moz.build b/image/decoders/icon/win/moz.build
index c89cec90ac8..886b42b05ad 100644
--- a/image/decoders/icon/win/moz.build
+++ b/image/decoders/icon/win/moz.build
@@ -12,3 +12,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'imgiconwin_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/image/decoders/moz.build b/image/decoders/moz.build
index 3b3874db734..4c520e6bea1 100644
--- a/image/decoders/moz.build
+++ b/image/decoders/moz.build
@@ -36,3 +36,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'imgdecoders_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/image/encoders/bmp/Makefile.in b/image/encoders/bmp/Makefile.in
index 0416c5b5194..df81ef0f7c0 100644
--- a/image/encoders/bmp/Makefile.in
+++ b/image/encoders/bmp/Makefile.in
@@ -10,8 +10,6 @@ VPATH		= @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 LOCAL_INCLUDES += -I$(topsrcdir)/image/src/
 
 include $(topsrcdir)/config/rules.mk
diff --git a/image/encoders/bmp/moz.build b/image/encoders/bmp/moz.build
index f9929ab5a41..c77ab50419e 100644
--- a/image/encoders/bmp/moz.build
+++ b/image/encoders/bmp/moz.build
@@ -12,3 +12,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'imgbmpe_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/image/encoders/ico/Makefile.in b/image/encoders/ico/Makefile.in
index 88c17df739f..65ecef1f80a 100644
--- a/image/encoders/ico/Makefile.in
+++ b/image/encoders/ico/Makefile.in
@@ -10,7 +10,6 @@ VPATH		= @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
 
 # Decoders need RasterImage.h
 LOCAL_INCLUDES += -I$(topsrcdir)/image/src/
diff --git a/image/encoders/ico/moz.build b/image/encoders/ico/moz.build
index fc01dd0de75..1008014be4d 100644
--- a/image/encoders/ico/moz.build
+++ b/image/encoders/ico/moz.build
@@ -12,3 +12,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'imgicoe_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/image/encoders/jpeg/Makefile.in b/image/encoders/jpeg/Makefile.in
index 93592f5c022..7051ddb33b2 100644
--- a/image/encoders/jpeg/Makefile.in
+++ b/image/encoders/jpeg/Makefile.in
@@ -10,8 +10,6 @@ VPATH		= @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
 
diff --git a/image/encoders/jpeg/moz.build b/image/encoders/jpeg/moz.build
index 8a3561752e5..a102612f17a 100644
--- a/image/encoders/jpeg/moz.build
+++ b/image/encoders/jpeg/moz.build
@@ -12,3 +12,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'imgjpege_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/image/encoders/png/Makefile.in b/image/encoders/png/Makefile.in
index 2797257edcf..acfb35f1640 100644
--- a/image/encoders/png/Makefile.in
+++ b/image/encoders/png/Makefile.in
@@ -10,8 +10,6 @@ VPATH		= @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 DEFINES		+= -DMOZ_PNG_WRITE \
 	-DMOZ_PNG_READ \
 	$(NULL)
diff --git a/image/encoders/png/moz.build b/image/encoders/png/moz.build
index e9db3c622e6..115220fdf82 100644
--- a/image/encoders/png/moz.build
+++ b/image/encoders/png/moz.build
@@ -12,3 +12,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'imgpnge_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/image/src/Makefile.in b/image/src/Makefile.in
index aa9ff826a95..e51378a2b7d 100644
--- a/image/src/Makefile.in
+++ b/image/src/Makefile.in
@@ -12,7 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME	= imglib2_s
 LIBXUL_LIBRARY  = 1
-FAIL_ON_WARNINGS = 1
 
 # We need to instantiate the decoders
 LOCAL_INCLUDES += -I$(topsrcdir)/image/decoders
diff --git a/image/src/moz.build b/image/src/moz.build
index fca3c903dcb..2257cbb7faf 100644
--- a/image/src/moz.build
+++ b/image/src/moz.build
@@ -38,3 +38,5 @@ CPP_SOURCES += [
     'imgTools.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/ipc/testshell/Makefile.in b/ipc/testshell/Makefile.in
index f4d679d2ef2..5667964f930 100644
--- a/ipc/testshell/Makefile.in
+++ b/ipc/testshell/Makefile.in
@@ -7,8 +7,6 @@ topsrcdir = @top_srcdir@
 srcdir = @srcdir@
 VPATH = @srcdir@
 relativesrcdir = @relativesrcdir@
-FAIL_ON_WARNINGS = 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME = ipcshell_s
diff --git a/ipc/testshell/moz.build b/ipc/testshell/moz.build
index fd5ea331736..f07e6e07363 100644
--- a/ipc/testshell/moz.build
+++ b/ipc/testshell/moz.build
@@ -26,3 +26,6 @@ IPDL_SOURCES = [
     'PTestShell.ipdl',
     'PTestShellCommand.ipdl',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/ipc/unixsocket/Makefile.in b/ipc/unixsocket/Makefile.in
index 906de43b3d2..0ee8f0a63cf 100644
--- a/ipc/unixsocket/Makefile.in
+++ b/ipc/unixsocket/Makefile.in
@@ -12,7 +12,5 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME = mozipcunixsocket_s
 LIBXUL_LIBRARY = 1
 EXPORT_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 include $(topsrcdir)/ipc/chromium/chromium-config.mk
diff --git a/ipc/unixsocket/moz.build b/ipc/unixsocket/moz.build
index 97ee8f94324..62c2246cc98 100644
--- a/ipc/unixsocket/moz.build
+++ b/ipc/unixsocket/moz.build
@@ -14,3 +14,5 @@ CPP_SOURCES += [
     'UnixSocket.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/js/ipc/Makefile.in b/js/ipc/Makefile.in
index 2d5dbca5da9..7f69c5df38a 100644
--- a/js/ipc/Makefile.in
+++ b/js/ipc/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME = jsipc_s
 LIBXUL_LIBRARY = 1
 EXPORT_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 LOCAL_INCLUDES += \
   -I$(topsrcdir)/dom/base \
   -I$(topsrcdir)/js/ipc \
diff --git a/js/ipc/moz.build b/js/ipc/moz.build
index 0e43d1cfdaa..4072cce1614 100644
--- a/js/ipc/moz.build
+++ b/js/ipc/moz.build
@@ -16,3 +16,6 @@ IPDL_SOURCES += [
     'JavaScriptTypes.ipdlh',
     'PJavaScript.ipdl',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/js/xpconnect/loader/Makefile.in b/js/xpconnect/loader/Makefile.in
index d0fabaabdb7..7bca49ca952 100644
--- a/js/xpconnect/loader/Makefile.in
+++ b/js/xpconnect/loader/Makefile.in
@@ -9,7 +9,6 @@ VPATH		= @srcdir@
 
 include $(DEPTH)/config/autoconf.mk
 
-FAIL_ON_WARNINGS := 1
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY = 1
 LOCAL_INCLUDES += \
diff --git a/js/xpconnect/loader/moz.build b/js/xpconnect/loader/moz.build
index b3f1105d929..6354453261d 100644
--- a/js/xpconnect/loader/moz.build
+++ b/js/xpconnect/loader/moz.build
@@ -18,3 +18,6 @@ EXTRA_JS_MODULES += [
     'ISO8601DateUtils.jsm',
     'XPCOMUtils.jsm',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/js/xpconnect/src/Makefile.in b/js/xpconnect/src/Makefile.in
index efe097acc23..53726b2821b 100644
--- a/js/xpconnect/src/Makefile.in
+++ b/js/xpconnect/src/Makefile.in
@@ -13,8 +13,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME    = xpconnect_s
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS := 1
-
 LOCAL_INCLUDES = \
 		-I$(srcdir)/../wrappers \
 		-I$(srcdir)/../loader \
diff --git a/js/xpconnect/src/moz.build b/js/xpconnect/src/moz.build
index 333faf7130f..6152158bd7a 100644
--- a/js/xpconnect/src/moz.build
+++ b/js/xpconnect/src/moz.build
@@ -53,3 +53,5 @@ CPP_SOURCES += [
     'nsXPConnect.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/js/xpconnect/wrappers/Makefile.in b/js/xpconnect/wrappers/Makefile.in
index d14718b6e3a..c4d4f89e7c7 100644
--- a/js/xpconnect/wrappers/Makefile.in
+++ b/js/xpconnect/wrappers/Makefile.in
@@ -11,9 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY = 1
-ifndef _MSC_VER # warning C4661 for FilteringWrapper
-FAIL_ON_WARNINGS := 1
-endif # !_MSC_VER
 
 LOCAL_INCLUDES = \
                 -I$(srcdir)/../src \
diff --git a/js/xpconnect/wrappers/moz.build b/js/xpconnect/wrappers/moz.build
index b41581a8543..461a0aa827b 100644
--- a/js/xpconnect/wrappers/moz.build
+++ b/js/xpconnect/wrappers/moz.build
@@ -21,3 +21,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'xpcwrappers_s'
 
+# warning C4661 for FilteringWrapper
+FAIL_ON_WARNINGS = not CONFIG['_MSC_VER']
diff --git a/layout/base/Makefile.in b/layout/base/Makefile.in
index 17adf29f9e3..9e61e0b25d5 100644
--- a/layout/base/Makefile.in
+++ b/layout/base/Makefile.in
@@ -13,8 +13,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME	= gkbase_s
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 include $(topsrcdir)/ipc/chromium/chromium-config.mk
 
diff --git a/layout/base/moz.build b/layout/base/moz.build
index da602b18270..2e96f1a02ee 100644
--- a/layout/base/moz.build
+++ b/layout/base/moz.build
@@ -99,3 +99,5 @@ CPP_SOURCES += [
     'nsStyleSheetService.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/layout/build/Makefile.in b/layout/build/Makefile.in
index 9bf88b09cdc..f405e43d8b4 100644
--- a/layout/build/Makefile.in
+++ b/layout/build/Makefile.in
@@ -19,9 +19,6 @@ LIBRARY_NAME	= gklayout
 MSVC_ENABLE_PGO := 1
 EXPORT_LIBRARY = 1
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
-
 SHARED_LIBRARY_LIBS = \
 	../base/$(LIB_PREFIX)gkbase_s.$(LIB_SUFFIX) \
 	../forms/$(LIB_PREFIX)gkforms_s.$(LIB_SUFFIX) \
diff --git a/layout/build/moz.build b/layout/build/moz.build
index fdb12f185b6..0e0b60575cf 100644
--- a/layout/build/moz.build
+++ b/layout/build/moz.build
@@ -18,3 +18,5 @@ CPP_SOURCES += [
     'nsLayoutStatics.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/layout/forms/Makefile.in b/layout/forms/Makefile.in
index 8d93c587bce..7b1250b5283 100644
--- a/layout/forms/Makefile.in
+++ b/layout/forms/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
 LOCAL_INCLUDES	= \
diff --git a/layout/forms/moz.build b/layout/forms/moz.build
index e090553c6e0..17baae71b8c 100644
--- a/layout/forms/moz.build
+++ b/layout/forms/moz.build
@@ -38,3 +38,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'gkforms_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/layout/generic/Makefile.in b/layout/generic/Makefile.in
index 270fa777b18..751c645430a 100644
--- a/layout/generic/Makefile.in
+++ b/layout/generic/Makefile.in
@@ -12,9 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME	= gkgeneric_s
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY	= 1
-ifndef _MSC_VER
-FAIL_ON_WARNINGS = 1
-endif # !_MSC_VER
 
 RESOURCES_HTML = \
 		$(srcdir)/folder.png \
diff --git a/layout/generic/moz.build b/layout/generic/moz.build
index aec4f4ce55e..d19c88c7d31 100644
--- a/layout/generic/moz.build
+++ b/layout/generic/moz.build
@@ -93,3 +93,5 @@ if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'cocoa':
     CMMSRCS += [
         'nsPluginUtilsOSX.mm',
     ]
+
+FAIL_ON_WARNINGS = not CONFIG['_MSC_VER']
diff --git a/layout/inspector/src/Makefile.in b/layout/inspector/src/Makefile.in
index 96ac0820501..83b0c9b077d 100644
--- a/layout/inspector/src/Makefile.in
+++ b/layout/inspector/src/Makefile.in
@@ -11,8 +11,6 @@ VPATH=@srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 LOCAL_INCLUDES	+= \
 		-I$(srcdir)/../../style \
 		-I$(topsrcdir)/content/base/src \
diff --git a/layout/inspector/src/moz.build b/layout/inspector/src/moz.build
index a70d4d98a17..abfb7dfc3a3 100644
--- a/layout/inspector/src/moz.build
+++ b/layout/inspector/src/moz.build
@@ -29,3 +29,5 @@ if CONFIG['MOZ_XUL']:
 
 LIBRARY_NAME = 'inspector_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/layout/ipc/Makefile.in b/layout/ipc/Makefile.in
index ebefc89a0eb..4aef1413816 100644
--- a/layout/ipc/Makefile.in
+++ b/layout/ipc/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME = gkipc_s
 LIBXUL_LIBRARY = 1
 EXPORT_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 include $(topsrcdir)/ipc/chromium/chromium-config.mk
 
diff --git a/layout/ipc/moz.build b/layout/ipc/moz.build
index 3f4e5f6646b..17ef8c16c3a 100644
--- a/layout/ipc/moz.build
+++ b/layout/ipc/moz.build
@@ -20,3 +20,6 @@ CPP_SOURCES += [
 IPDL_SOURCES = [
     'PRenderFrame.ipdl',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/layout/mathml/Makefile.in b/layout/mathml/Makefile.in
index 12bec4cb358..f5422381cd3 100644
--- a/layout/mathml/Makefile.in
+++ b/layout/mathml/Makefile.in
@@ -13,9 +13,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME = gkmathml_s
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
-
 LOCAL_INCLUDES = \
 	-I$(srcdir)/../style \
 	-I$(srcdir)/../base \
diff --git a/layout/mathml/moz.build b/layout/mathml/moz.build
index 586bcf60f27..56e56e95786 100644
--- a/layout/mathml/moz.build
+++ b/layout/mathml/moz.build
@@ -31,3 +31,5 @@ CPP_SOURCES += [
     'nsMathMLsemanticsFrame.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/layout/printing/Makefile.in b/layout/printing/Makefile.in
index 77bb2ea8476..01d78ecf157 100644
--- a/layout/printing/Makefile.in
+++ b/layout/printing/Makefile.in
@@ -10,8 +10,6 @@ VPATH		= @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
 LOCAL_INCLUDES += \
diff --git a/layout/printing/moz.build b/layout/printing/moz.build
index 152a3587c0b..18273864fab 100644
--- a/layout/printing/moz.build
+++ b/layout/printing/moz.build
@@ -24,3 +24,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'gkprinting_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/layout/style/Makefile.in b/layout/style/Makefile.in
index 983e9cca3cf..beba3c48de9 100644
--- a/layout/style/Makefile.in
+++ b/layout/style/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME	= gkstyle_s
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 ifdef GNU_CC
 OS_CFLAGS := $(OS_CFLAGS) -Wshadow
 OS_CXXFLAGS := $(OS_CXXFLAGS) -Wshadow
diff --git a/layout/style/moz.build b/layout/style/moz.build
index e00e8491789..ac7f4d9cd73 100644
--- a/layout/style/moz.build
+++ b/layout/style/moz.build
@@ -123,3 +123,5 @@ CPP_SOURCES += [
     'nsTransitionManager.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/layout/svg/Makefile.in b/layout/svg/Makefile.in
index ed32b433f1a..ba77befc186 100644
--- a/layout/svg/Makefile.in
+++ b/layout/svg/Makefile.in
@@ -12,9 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME	= gksvgbase_s
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
-
 include $(topsrcdir)/config/rules.mk
 
 LOCAL_INCLUDES	= \
diff --git a/layout/svg/moz.build b/layout/svg/moz.build
index 49880173c2d..16c80c0db46 100644
--- a/layout/svg/moz.build
+++ b/layout/svg/moz.build
@@ -53,3 +53,5 @@ CPP_SOURCES += [
     'nsSVGUtils.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/layout/tables/Makefile.in b/layout/tables/Makefile.in
index dca53289dc6..dcbcc95d968 100644
--- a/layout/tables/Makefile.in
+++ b/layout/tables/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
 DEFINES         += -DDEBUG_TABLE_STRATEGY_off
diff --git a/layout/tables/moz.build b/layout/tables/moz.build
index 025bb76dbd5..32ad123f1b9 100644
--- a/layout/tables/moz.build
+++ b/layout/tables/moz.build
@@ -29,3 +29,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'gktable_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/layout/tools/layout-debug/src/Makefile.in b/layout/tools/layout-debug/src/Makefile.in
index ef44ae04c8f..559ca83e300 100644
--- a/layout/tools/layout-debug/src/Makefile.in
+++ b/layout/tools/layout-debug/src/Makefile.in
@@ -12,9 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 EXPORT_LIBRARY	= 1
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
-
 include $(topsrcdir)/config/rules.mk
 
 libs::
diff --git a/layout/tools/layout-debug/src/moz.build b/layout/tools/layout-debug/src/moz.build
index fd03b581894..a97ceb9d9c8 100644
--- a/layout/tools/layout-debug/src/moz.build
+++ b/layout/tools/layout-debug/src/moz.build
@@ -24,3 +24,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'gkdebug'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/layout/xul/base/src/Makefile.in b/layout/xul/base/src/Makefile.in
index 15327dd5e5b..b30ab753c65 100644
--- a/layout/xul/base/src/Makefile.in
+++ b/layout/xul/base/src/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME	= gkxulbase_s
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
 LOCAL_INCLUDES	= \
diff --git a/layout/xul/base/src/moz.build b/layout/xul/base/src/moz.build
index 6f27f45c6ac..d3784f00f7e 100644
--- a/layout/xul/base/src/moz.build
+++ b/layout/xul/base/src/moz.build
@@ -53,3 +53,6 @@ if CONFIG['MOZ_XUL']:
         'nsXULLabelFrame.cpp',
         'nsXULPopupManager.cpp',
     ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/layout/xul/grid/Makefile.in b/layout/xul/grid/Makefile.in
index 3dfb63e5ccf..14b3c846afa 100644
--- a/layout/xul/grid/Makefile.in
+++ b/layout/xul/grid/Makefile.in
@@ -11,8 +11,6 @@ VPATH		= @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY  = 1
-FAIL_ON_WARNINGS = 1
-
 LOCAL_INCLUDES	= \
 		-I$(srcdir) \
 		-I$(srcdir)/../base/src \
diff --git a/layout/xul/grid/moz.build b/layout/xul/grid/moz.build
index d2cfd5d2e25..f8be16873db 100644
--- a/layout/xul/grid/moz.build
+++ b/layout/xul/grid/moz.build
@@ -32,3 +32,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'gkxulgrid_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/layout/xul/tree/Makefile.in b/layout/xul/tree/Makefile.in
index e0f6b11a034..90fdeda400d 100644
--- a/layout/xul/tree/Makefile.in
+++ b/layout/xul/tree/Makefile.in
@@ -11,8 +11,6 @@ VPATH		= @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY  = 1
-FAIL_ON_WARNINGS = 1
-
 LOCAL_INCLUDES	= \
 		-I$(srcdir) \
 		-I$(topsrcdir)/content/events/src \
diff --git a/layout/xul/tree/moz.build b/layout/xul/tree/moz.build
index 8add51baf87..79175b60ca1 100644
--- a/layout/xul/tree/moz.build
+++ b/layout/xul/tree/moz.build
@@ -35,3 +35,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'gkxultree_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/media/mtransport/build/Makefile.in b/media/mtransport/build/Makefile.in
index 40a950a1c47..35ab5736922 100644
--- a/media/mtransport/build/Makefile.in
+++ b/media/mtransport/build/Makefile.in
@@ -17,10 +17,6 @@ endif
 
 LIBXUL_LIBRARY=1
 
-ifndef _MSC_VER
-FAIL_ON_WARNINGS = 1
-endif # !_MSC_VER
-
 include $(srcdir)/../objs.mk
 
 
diff --git a/media/mtransport/build/moz.build b/media/mtransport/build/moz.build
index dc9e3e19ddb..c439df6fa4a 100644
--- a/media/mtransport/build/moz.build
+++ b/media/mtransport/build/moz.build
@@ -30,3 +30,4 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'mtransport'
 
+FAIL_ON_WARNINGS = not CONFIG['_MSC_VER']
diff --git a/media/mtransport/test/Makefile.in b/media/mtransport/test/Makefile.in
index ef01fd89779..47c35e3e188 100644
--- a/media/mtransport/test/Makefile.in
+++ b/media/mtransport/test/Makefile.in
@@ -9,8 +9,6 @@ VPATH = @srcdir@
 
 include $(DEPTH)/config/autoconf.mk
 
-FAIL_ON_WARNINGS = 1
-
 DEFINES += \
   -DHAVE_STRDUP -DNR_SOCKET_IS_VOID_PTR -DSCTP_DEBUG -DINET
 
diff --git a/media/mtransport/test/moz.build b/media/mtransport/test/moz.build
index 4fd84d59ac9..e1520fcf6c6 100644
--- a/media/mtransport/test/moz.build
+++ b/media/mtransport/test/moz.build
@@ -21,3 +21,6 @@ if CONFIG['OS_TARGET'] != 'WINNT' and CONFIG['MOZ_WIDGET_TOOLKIT'] != 'gonk':
         CPP_UNIT_TESTS += [
             'sctp_unittest.cpp',
         ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/modules/libjar/Makefile.in b/modules/libjar/Makefile.in
index a66a38ea726..b07372507c2 100644
--- a/modules/libjar/Makefile.in
+++ b/modules/libjar/Makefile.in
@@ -14,7 +14,5 @@ LIBRARY_NAME	= jar$(VERSION_NUMBER)
 MSVC_ENABLE_PGO := 1
 EXPORT_LIBRARY = 1
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 include $(topsrcdir)/ipc/chromium/chromium-config.mk
diff --git a/modules/libjar/moz.build b/modules/libjar/moz.build
index 7b132d7e103..1fdbc429832 100644
--- a/modules/libjar/moz.build
+++ b/modules/libjar/moz.build
@@ -34,3 +34,5 @@ CPP_SOURCES += [
     'nsZipArchive.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/mozglue/android/Makefile.in b/mozglue/android/Makefile.in
index a67c4d45041..d3ac49fcb9e 100644
--- a/mozglue/android/Makefile.in
+++ b/mozglue/android/Makefile.in
@@ -11,8 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 FORCE_STATIC_LIB = 1
 STL_FLAGS=
-FAIL_ON_WARNINGS := 1
-
 DEFINES += \
   -DANDROID_PACKAGE_NAME='"$(ANDROID_PACKAGE_NAME)"' \
   $(NULL)
diff --git a/mozglue/android/moz.build b/mozglue/android/moz.build
index 48722a8e86d..37f165fe1b8 100644
--- a/mozglue/android/moz.build
+++ b/mozglue/android/moz.build
@@ -19,3 +19,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'android'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/base/public/Makefile.in b/netwerk/base/public/Makefile.in
index 45531d6beca..11a39f90e87 100644
--- a/netwerk/base/public/Makefile.in
+++ b/netwerk/base/public/Makefile.in
@@ -7,8 +7,6 @@ DEPTH		= @DEPTH@
 topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 
diff --git a/netwerk/base/public/moz.build b/netwerk/base/public/moz.build
index f39509709c4..4abb5b910ff 100644
--- a/netwerk/base/public/moz.build
+++ b/netwerk/base/public/moz.build
@@ -134,3 +134,5 @@ EXPORTS += [
     'nsURIHashKey.h',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/base/src/Makefile.in b/netwerk/base/src/Makefile.in
index 00208d1262f..6b734e1ab33 100644
--- a/netwerk/base/src/Makefile.in
+++ b/netwerk/base/src/Makefile.in
@@ -14,8 +14,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME	= neckobase_s
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY  = 1
-FAIL_ON_WARNINGS := 1
-
 LOCAL_INCLUDES	+= -I$(topsrcdir)/dom/base
 
 ifdef MOZ_PLATFORM_MAEMO
diff --git a/netwerk/base/src/moz.build b/netwerk/base/src/moz.build
index 2af05e25280..bfc82ab119d 100644
--- a/netwerk/base/src/moz.build
+++ b/netwerk/base/src/moz.build
@@ -110,3 +110,6 @@ if CONFIG['MOZ_PLATFORM_MAEMO']:
 EXTRA_JS_MODULES += [
     'NetUtil.jsm',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/build/Makefile.in b/netwerk/build/Makefile.in
index 179d43d7517..40a348dde95 100644
--- a/netwerk/build/Makefile.in
+++ b/netwerk/build/Makefile.in
@@ -14,8 +14,6 @@ LIBRARY_NAME   = necko
 MSVC_ENABLE_PGO := 1
 EXPORT_LIBRARY = 1
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS := 1
-
 SHARED_LIBRARY_LIBS = \
   ../base/src/$(LIB_PREFIX)neckobase_s.$(LIB_SUFFIX) \
   ../dns/$(LIB_PREFIX)neckodns_s.$(LIB_SUFFIX) \
diff --git a/netwerk/build/moz.build b/netwerk/build/moz.build
index 987d4da8656..268b5e93311 100644
--- a/netwerk/build/moz.build
+++ b/netwerk/build/moz.build
@@ -14,3 +14,5 @@ CPP_SOURCES += [
     'nsNetModule.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/cache/Makefile.in b/netwerk/cache/Makefile.in
index 504f608b683..a7f65e02c82 100644
--- a/netwerk/cache/Makefile.in
+++ b/netwerk/cache/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS := 1
-
 LOCAL_INCLUDES = \
   -I$(srcdir)/../base/src \
   $(NULL)
diff --git a/netwerk/cache/moz.build b/netwerk/cache/moz.build
index ba048016d03..3bbaff6f0df 100644
--- a/netwerk/cache/moz.build
+++ b/netwerk/cache/moz.build
@@ -44,3 +44,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'nkcache_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/cookie/Makefile.in b/netwerk/cookie/Makefile.in
index ad683994268..2090ea61bef 100644
--- a/netwerk/cookie/Makefile.in
+++ b/netwerk/cookie/Makefile.in
@@ -12,8 +12,6 @@ relativesrcdir = @relativesrcdir@
 include $(DEPTH)/config/autoconf.mk
 
 # export required interfaces, even if --disable-cookies has been given
-FAIL_ON_WARNINGS := 1
-
 ifdef NECKO_COOKIES
 LIBRARY_NAME     = neckocookie_s
 MSVC_ENABLE_PGO := 1
diff --git a/netwerk/cookie/moz.build b/netwerk/cookie/moz.build
index 4189aa76bb5..d07a9f4f29f 100644
--- a/netwerk/cookie/moz.build
+++ b/netwerk/cookie/moz.build
@@ -39,3 +39,6 @@ if CONFIG['NECKO_COOKIES'] and CONFIG['OS_ARCH'] != 'Darwin':
 IPDL_SOURCES = [
     'PCookieService.ipdl',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/dns/Makefile.in b/netwerk/dns/Makefile.in
index 03a9c5c1673..2e9e3a4c928 100644
--- a/netwerk/dns/Makefile.in
+++ b/netwerk/dns/Makefile.in
@@ -12,7 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS := 1
 
 # need to include etld_data.inc
 LOCAL_INCLUDES = \
diff --git a/netwerk/dns/moz.build b/netwerk/dns/moz.build
index 093f6f746fa..db682fab037 100644
--- a/netwerk/dns/moz.build
+++ b/netwerk/dns/moz.build
@@ -37,3 +37,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'neckodns_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/ipc/Makefile.in b/netwerk/ipc/Makefile.in
index 2c2c15ce106..8388a674fec 100644
--- a/netwerk/ipc/Makefile.in
+++ b/netwerk/ipc/Makefile.in
@@ -6,8 +6,6 @@ DEPTH = @DEPTH@
 topsrcdir = @top_srcdir@
 srcdir = @srcdir@
 VPATH = @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME = neckoipc_s
diff --git a/netwerk/ipc/moz.build b/netwerk/ipc/moz.build
index c4094c91feb..b3fbb6f8bb0 100644
--- a/netwerk/ipc/moz.build
+++ b/netwerk/ipc/moz.build
@@ -36,3 +36,6 @@ IPDL_SOURCES = [
     'PNecko.ipdl',
     'PRemoteOpenFile.ipdl',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/mime/Makefile.in b/netwerk/mime/Makefile.in
index 8f31acf4d80..3bcbb57a245 100644
--- a/netwerk/mime/Makefile.in
+++ b/netwerk/mime/Makefile.in
@@ -7,8 +7,6 @@ DEPTH     = @DEPTH@
 topsrcdir = @top_srcdir@
 srcdir    = @srcdir@
 VPATH     = @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 MSVC_ENABLE_PGO := 1
diff --git a/netwerk/mime/moz.build b/netwerk/mime/moz.build
index 2f241e7f247..e3f3179d662 100644
--- a/netwerk/mime/moz.build
+++ b/netwerk/mime/moz.build
@@ -22,3 +22,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'nkmime_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/protocol/about/Makefile.in b/netwerk/protocol/about/Makefile.in
index c5011f2cce9..f825d7cb5e5 100644
--- a/netwerk/protocol/about/Makefile.in
+++ b/netwerk/protocol/about/Makefile.in
@@ -7,8 +7,6 @@ DEPTH     = @DEPTH@
 topsrcdir = @top_srcdir@
 srcdir    = @srcdir@
 VPATH     = @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME   = nkabout_s
diff --git a/netwerk/protocol/about/moz.build b/netwerk/protocol/about/moz.build
index 3892cb706eb..65333a58584 100644
--- a/netwerk/protocol/about/moz.build
+++ b/netwerk/protocol/about/moz.build
@@ -24,3 +24,5 @@ CPP_SOURCES += [
     'nsAboutProtocolHandler.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/protocol/data/Makefile.in b/netwerk/protocol/data/Makefile.in
index 82157dddcb8..659bd99d247 100644
--- a/netwerk/protocol/data/Makefile.in
+++ b/netwerk/protocol/data/Makefile.in
@@ -7,8 +7,6 @@ DEPTH     = @DEPTH@
 topsrcdir = @top_srcdir@
 srcdir    = @srcdir@
 VPATH     = @srcdir@
-FAIL_ON_WARNINGS = 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
diff --git a/netwerk/protocol/data/moz.build b/netwerk/protocol/data/moz.build
index 3d4344b541d..f4bcf8e60f4 100644
--- a/netwerk/protocol/data/moz.build
+++ b/netwerk/protocol/data/moz.build
@@ -13,3 +13,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'nkdata_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/protocol/device/Makefile.in b/netwerk/protocol/device/Makefile.in
index 3437d16c5be..30558cc495e 100644
--- a/netwerk/protocol/device/Makefile.in
+++ b/netwerk/protocol/device/Makefile.in
@@ -6,8 +6,6 @@ DEPTH     = @DEPTH@
 topsrcdir = @top_srcdir@
 srcdir    = @srcdir@
 VPATH     = @srcdir@
-FAIL_ON_WARNINGS = 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME = nkdevice_s
diff --git a/netwerk/protocol/device/moz.build b/netwerk/protocol/device/moz.build
index 147c8eb2af4..e2c5b2898cb 100644
--- a/netwerk/protocol/device/moz.build
+++ b/netwerk/protocol/device/moz.build
@@ -20,3 +20,5 @@ CPP_SOURCES += [
     'nsDeviceProtocolHandler.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/protocol/file/Makefile.in b/netwerk/protocol/file/Makefile.in
index 1ff638f3323..4a3e4456da4 100644
--- a/netwerk/protocol/file/Makefile.in
+++ b/netwerk/protocol/file/Makefile.in
@@ -7,8 +7,6 @@ DEPTH     = @DEPTH@
 topsrcdir = @top_srcdir@
 srcdir    = @srcdir@
 VPATH     = @srcdir@
-FAIL_ON_WARNINGS = 1
-
 include $(DEPTH)/config/autoconf.mk
 
 MSVC_ENABLE_PGO := 1
diff --git a/netwerk/protocol/file/moz.build b/netwerk/protocol/file/moz.build
index e3eb168ec78..b5fa3c9666b 100644
--- a/netwerk/protocol/file/moz.build
+++ b/netwerk/protocol/file/moz.build
@@ -20,3 +20,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'nkfile_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/protocol/ftp/Makefile.in b/netwerk/protocol/ftp/Makefile.in
index bd92e69a511..96b5df04712 100644
--- a/netwerk/protocol/ftp/Makefile.in
+++ b/netwerk/protocol/ftp/Makefile.in
@@ -7,8 +7,6 @@ DEPTH     = @DEPTH@
 topsrcdir = @top_srcdir@
 srcdir    = @srcdir@
 VPATH     = @srcdir@
-FAIL_ON_WARNINGS = 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME   = nkftp_s
diff --git a/netwerk/protocol/ftp/moz.build b/netwerk/protocol/ftp/moz.build
index 232e8b20981..2b080f82c3e 100644
--- a/netwerk/protocol/ftp/moz.build
+++ b/netwerk/protocol/ftp/moz.build
@@ -33,3 +33,6 @@ CPP_SOURCES += [
 IPDL_SOURCES += [
     'PFTPChannel.ipdl',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/protocol/http/Makefile.in b/netwerk/protocol/http/Makefile.in
index 640b1f0e7d6..90d296925a4 100644
--- a/netwerk/protocol/http/Makefile.in
+++ b/netwerk/protocol/http/Makefile.in
@@ -13,8 +13,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME   = nkhttp_s
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS := 1
-
 LOCAL_INCLUDES = \
   -I$(srcdir)/../../base/src \
   -I$(topsrcdir)/xpcom/ds \
diff --git a/netwerk/protocol/http/moz.build b/netwerk/protocol/http/moz.build
index 6add00fed3c..5e81cea1e35 100644
--- a/netwerk/protocol/http/moz.build
+++ b/netwerk/protocol/http/moz.build
@@ -79,3 +79,6 @@ IPDL_SOURCES += [
 EXTRA_JS_MODULES += [
     'UserAgentOverrides.jsm',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/protocol/res/Makefile.in b/netwerk/protocol/res/Makefile.in
index af6eb70aa45..dbc937e0ef0 100644
--- a/netwerk/protocol/res/Makefile.in
+++ b/netwerk/protocol/res/Makefile.in
@@ -13,8 +13,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME   = nkres_s
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 LOCAL_INCLUDES = \
   -I$(topsrcdir)/netwerk/base/src \
   $(NULL)
diff --git a/netwerk/protocol/res/moz.build b/netwerk/protocol/res/moz.build
index 9cd1568e6f4..46ddeeade9c 100644
--- a/netwerk/protocol/res/moz.build
+++ b/netwerk/protocol/res/moz.build
@@ -16,3 +16,5 @@ CPP_SOURCES += [
     'nsResProtocolHandler.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/protocol/viewsource/Makefile.in b/netwerk/protocol/viewsource/Makefile.in
index 7057c582923..d34433c5562 100644
--- a/netwerk/protocol/viewsource/Makefile.in
+++ b/netwerk/protocol/viewsource/Makefile.in
@@ -7,8 +7,6 @@ DEPTH     = @DEPTH@
 topsrcdir = @top_srcdir@
 srcdir    = @srcdir@
 VPATH     = @srcdir@
-FAIL_ON_WARNINGS = 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
diff --git a/netwerk/protocol/viewsource/moz.build b/netwerk/protocol/viewsource/moz.build
index 22a818b54f2..f93e6d11127 100644
--- a/netwerk/protocol/viewsource/moz.build
+++ b/netwerk/protocol/viewsource/moz.build
@@ -19,3 +19,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'nkviewsource_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/protocol/websocket/Makefile.in b/netwerk/protocol/websocket/Makefile.in
index cdf1e7c66dd..96e6e1cdbf4 100644
--- a/netwerk/protocol/websocket/Makefile.in
+++ b/netwerk/protocol/websocket/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME   = nkwebsocket_s
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 LOCAL_INCLUDES = \
   -I$(srcdir)/../../base/src \
   -I$(topsrcdir)/content/base/src \
diff --git a/netwerk/protocol/websocket/moz.build b/netwerk/protocol/websocket/moz.build
index e1dde568db6..c4cb901cd19 100644
--- a/netwerk/protocol/websocket/moz.build
+++ b/netwerk/protocol/websocket/moz.build
@@ -30,3 +30,6 @@ CPP_SOURCES += [
 IPDL_SOURCES += [
     'PWebSocket.ipdl',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/protocol/wyciwyg/Makefile.in b/netwerk/protocol/wyciwyg/Makefile.in
index ff14c12394d..e7f3b0be4a5 100644
--- a/netwerk/protocol/wyciwyg/Makefile.in
+++ b/netwerk/protocol/wyciwyg/Makefile.in
@@ -11,8 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME	= nkwyciwyg_s
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 LOCAL_INCLUDES = \
   -I$(srcdir)/../../base/src \
   $(NULL)
diff --git a/netwerk/protocol/wyciwyg/moz.build b/netwerk/protocol/wyciwyg/moz.build
index 21c2489d5f6..dbb94052d3b 100644
--- a/netwerk/protocol/wyciwyg/moz.build
+++ b/netwerk/protocol/wyciwyg/moz.build
@@ -28,3 +28,6 @@ CPP_SOURCES += [
 IPDL_SOURCES += [
     'PWyciwygChannel.ipdl',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/sctp/datachannel/Makefile.in b/netwerk/sctp/datachannel/Makefile.in
index c37b57f2da3..9d79fb1e094 100644
--- a/netwerk/sctp/datachannel/Makefile.in
+++ b/netwerk/sctp/datachannel/Makefile.in
@@ -13,8 +13,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME   = nkdatachan_s
 LIBXUL_LIBRARY = 1
 NO_PROFILE_GUIDED_OPTIMIZE = 1 # Don't PGO
-FAIL_ON_WARNINGS = 1
-
 LOCAL_INCLUDES = \
   -I$(topsrcdir)/xpcom/ds \
   -I$(srcdir)/../src \
diff --git a/netwerk/sctp/datachannel/moz.build b/netwerk/sctp/datachannel/moz.build
index bf6e9be7cd9..f16756498b2 100644
--- a/netwerk/sctp/datachannel/moz.build
+++ b/netwerk/sctp/datachannel/moz.build
@@ -17,3 +17,5 @@ CPP_SOURCES += [
     'DataChannel.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/socket/Makefile.in b/netwerk/socket/Makefile.in
index 361ed47544b..22f2bacadc9 100644
--- a/netwerk/socket/Makefile.in
+++ b/netwerk/socket/Makefile.in
@@ -7,8 +7,6 @@ DEPTH     = @DEPTH@
 topsrcdir = @top_srcdir@
 srcdir    = @srcdir@
 VPATH     = @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
diff --git a/netwerk/socket/moz.build b/netwerk/socket/moz.build
index c25d3b58bff..b0b5f0de06b 100644
--- a/netwerk/socket/moz.build
+++ b/netwerk/socket/moz.build
@@ -25,3 +25,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'neckosocket_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/streamconv/converters/Makefile.in b/netwerk/streamconv/converters/Makefile.in
index 486169e9d43..791852c497b 100644
--- a/netwerk/streamconv/converters/Makefile.in
+++ b/netwerk/streamconv/converters/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS := 1
-
 LOCAL_INCLUDES =                        \
         -I$(topsrcdir)/netwerk/base/src \
         $(NULL)
diff --git a/netwerk/streamconv/converters/moz.build b/netwerk/streamconv/converters/moz.build
index 2786427d072..0d0d90c51c7 100644
--- a/netwerk/streamconv/converters/moz.build
+++ b/netwerk/streamconv/converters/moz.build
@@ -30,3 +30,5 @@ if CONFIG['MOZ_WIDGET_TOOLKIT'] != 'cocoa':
 
 LIBRARY_NAME = 'nkcnvts_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/streamconv/public/Makefile.in b/netwerk/streamconv/public/Makefile.in
deleted file mode 100644
index 711d3c09115..00000000000
--- a/netwerk/streamconv/public/Makefile.in
+++ /dev/null
@@ -1,16 +0,0 @@
-#
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-DEPTH		= @DEPTH@
-topsrcdir	= @top_srcdir@
-srcdir		= @srcdir@
-VPATH		= @srcdir@
-FAIL_ON_WARNINGS := 1
-
-include $(DEPTH)/config/autoconf.mk
-
-
-include $(topsrcdir)/config/rules.mk
-
diff --git a/netwerk/streamconv/public/moz.build b/netwerk/streamconv/public/moz.build
index 3efb0619f9e..47ced496802 100644
--- a/netwerk/streamconv/public/moz.build
+++ b/netwerk/streamconv/public/moz.build
@@ -22,3 +22,5 @@ XPIDL_MODULE = 'necko_strconv'
 
 MODULE = 'necko'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/streamconv/src/Makefile.in b/netwerk/streamconv/src/Makefile.in
index fd890872574..c0cab172f78 100644
--- a/netwerk/streamconv/src/Makefile.in
+++ b/netwerk/streamconv/src/Makefile.in
@@ -13,12 +13,5 @@ include $(DEPTH)/config/autoconf.mk
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY  = 1
 
-ifneq (cocoa,$(MOZ_WIDGET_TOOLKIT))
-ifeq (x86_64,$(OS_TEST))
-# nsAppleFileDecoder.cpp has warnings I don't understand.
-FAIL_ON_WARNINGS := 1
-endif
-endif
-
 include $(topsrcdir)/config/rules.mk
 
diff --git a/netwerk/streamconv/src/moz.build b/netwerk/streamconv/src/moz.build
index ee6d24d0768..360dd22be4b 100644
--- a/netwerk/streamconv/src/moz.build
+++ b/netwerk/streamconv/src/moz.build
@@ -6,15 +6,18 @@
 
 MODULE = 'necko'
 
+FAIL_ON_WARNINGS = True
+
 CPP_SOURCES += [
     'nsStreamConverterService.cpp',
 ]
 
-if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'cocoa':
-    if CONFIG['OS_TEST'] != 'x86_64':
-        CPP_SOURCES += [
-            'nsAppleFileDecoder.cpp',
-        ]
+if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'cocoa' and CONFIG['OS_TEST'] != 'x86_64':
+    # nsAppleFileDecoder.cpp has warnings I don't understand.
+    FAIL_ON_WARNINGS = False
+    CPP_SOURCES += [
+        'nsAppleFileDecoder.cpp',
+    ]
 
 LIBRARY_NAME = 'nkconv_s'
 
diff --git a/netwerk/streamconv/test/Makefile.in b/netwerk/streamconv/test/Makefile.in
index 43d0e647e84..360a151c606 100644
--- a/netwerk/streamconv/test/Makefile.in
+++ b/netwerk/streamconv/test/Makefile.in
@@ -7,8 +7,6 @@ DEPTH		= @DEPTH@
 topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBS		= \
diff --git a/netwerk/streamconv/test/moz.build b/netwerk/streamconv/test/moz.build
index 1dc3688dcb5..4526dc0e888 100644
--- a/netwerk/streamconv/test/moz.build
+++ b/netwerk/streamconv/test/moz.build
@@ -12,3 +12,6 @@ CPP_SOURCES += [
     'Converters.cpp',
     'TestStreamConv.cpp',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/system/android/Makefile.in b/netwerk/system/android/Makefile.in
index 38abf5c61d9..ae8891478d7 100644
--- a/netwerk/system/android/Makefile.in
+++ b/netwerk/system/android/Makefile.in
@@ -6,8 +6,6 @@ DEPTH		= @DEPTH@
 topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
diff --git a/netwerk/system/android/moz.build b/netwerk/system/android/moz.build
index 9f95b11de1f..22d5f3096b7 100644
--- a/netwerk/system/android/moz.build
+++ b/netwerk/system/android/moz.build
@@ -12,3 +12,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'neckosystem_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/system/mac/Makefile.in b/netwerk/system/mac/Makefile.in
index 211db0b53f4..c060b2970fc 100644
--- a/netwerk/system/mac/Makefile.in
+++ b/netwerk/system/mac/Makefile.in
@@ -7,8 +7,6 @@ DEPTH		= @DEPTH@
 topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
diff --git a/netwerk/system/mac/moz.build b/netwerk/system/mac/moz.build
index 10805e74668..01dcb59559d 100644
--- a/netwerk/system/mac/moz.build
+++ b/netwerk/system/mac/moz.build
@@ -11,3 +11,6 @@ LIBRARY_NAME = 'neckosystem_s'
 CMMSRCS += [
     'nsNetworkLinkService.mm',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/system/maemo/Makefile.in b/netwerk/system/maemo/Makefile.in
index 18758f44715..6f23cb56efb 100644
--- a/netwerk/system/maemo/Makefile.in
+++ b/netwerk/system/maemo/Makefile.in
@@ -6,8 +6,6 @@ DEPTH		= @DEPTH@
 topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
diff --git a/netwerk/system/maemo/moz.build b/netwerk/system/maemo/moz.build
index ccabe2b608e..6382d413d0b 100644
--- a/netwerk/system/maemo/moz.build
+++ b/netwerk/system/maemo/moz.build
@@ -13,3 +13,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'neckosystem_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/system/qt/Makefile.in b/netwerk/system/qt/Makefile.in
index 9e69c12f489..169519f6819 100644
--- a/netwerk/system/qt/Makefile.in
+++ b/netwerk/system/qt/Makefile.in
@@ -7,8 +7,6 @@ DEPTH		= @DEPTH@
 topsrcdir	= @top_srcdir@
 srcdir	 = @srcdir@
 VPATH		= @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
diff --git a/netwerk/system/qt/moz.build b/netwerk/system/qt/moz.build
index 10f228e9236..b5ef3112844 100644
--- a/netwerk/system/qt/moz.build
+++ b/netwerk/system/qt/moz.build
@@ -14,3 +14,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'neckosystem_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/system/win32/Makefile.in b/netwerk/system/win32/Makefile.in
index 211db0b53f4..c060b2970fc 100644
--- a/netwerk/system/win32/Makefile.in
+++ b/netwerk/system/win32/Makefile.in
@@ -7,8 +7,6 @@ DEPTH		= @DEPTH@
 topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
diff --git a/netwerk/system/win32/moz.build b/netwerk/system/win32/moz.build
index 98fee928e26..3065cbdf047 100644
--- a/netwerk/system/win32/moz.build
+++ b/netwerk/system/win32/moz.build
@@ -13,3 +13,5 @@ if CONFIG['OS_ARCH'] == 'WINNT':
 
 LIBRARY_NAME = 'neckosystem_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/test/mochitests/Makefile.in b/netwerk/test/mochitests/Makefile.in
index e1dd425ddb4..30311a97b7b 100644
--- a/netwerk/test/mochitests/Makefile.in
+++ b/netwerk/test/mochitests/Makefile.in
@@ -9,8 +9,6 @@ topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
 relativesrcdir	= @relativesrcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 MOCHITEST_FILES = \
diff --git a/netwerk/test/mochitests/moz.build b/netwerk/test/mochitests/moz.build
index a6f020189e9..d731280b64f 100644
--- a/netwerk/test/mochitests/moz.build
+++ b/netwerk/test/mochitests/moz.build
@@ -5,3 +5,6 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 MODULE = 'test_necko'
+
+FAIL_ON_WARNINGS = True
+
diff --git a/netwerk/wifi/Makefile.in b/netwerk/wifi/Makefile.in
index 4cbf912d87b..e9a9ebb5231 100644
--- a/netwerk/wifi/Makefile.in
+++ b/netwerk/wifi/Makefile.in
@@ -11,11 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
 
-ifneq ($(OS_ARCH),Darwin)
-# osx_corewlan.mm has warnings I don't understand.
-FAIL_ON_WARNINGS := 1
-endif
-
 ifeq ($(OS_ARCH),SunOS)
 OS_INCLUDES += $(GLIB_CFLAGS)
 endif
diff --git a/netwerk/wifi/moz.build b/netwerk/wifi/moz.build
index 07b01de7577..29abb6b02cb 100644
--- a/netwerk/wifi/moz.build
+++ b/netwerk/wifi/moz.build
@@ -4,6 +4,8 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
+FAIL_ON_WARNINGS = True
+
 XPIDL_SOURCES += [
     'nsIWifiAccessPoint.idl',
     'nsIWifiListener.idl',
@@ -28,6 +30,8 @@ else:
     ]
 
 if CONFIG['OS_ARCH'] == 'Darwin':
+    # osx_corewlan.mm has warnings I don't understand.
+    FAIL_ON_WARNINGS = False
     CPP_SOURCES += [
         'nsWifiScannerMac.cpp',
     ]
diff --git a/security/manager/boot/src/Makefile.in b/security/manager/boot/src/Makefile.in
index bcf81ce7471..49c99d7142d 100644
--- a/security/manager/boot/src/Makefile.in
+++ b/security/manager/boot/src/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 MSVC_ENABLE_PGO := 1
 EXPORT_LIBRARY	= 1
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 DEFINES += -D__STDC_CONSTANT_MACROS
 
 include $(topsrcdir)/config/rules.mk
diff --git a/security/manager/boot/src/moz.build b/security/manager/boot/src/moz.build
index 865030329d2..563c8d697d3 100644
--- a/security/manager/boot/src/moz.build
+++ b/security/manager/boot/src/moz.build
@@ -17,3 +17,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'pipboot'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/security/manager/pki/src/Makefile.in b/security/manager/pki/src/Makefile.in
index 4210dda8e23..d4db5579906 100644
--- a/security/manager/pki/src/Makefile.in
+++ b/security/manager/pki/src/Makefile.in
@@ -13,8 +13,6 @@ include $(DEPTH)/config/autoconf.mk
 
 EXPORT_LIBRARY	= 1
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 INCLUDES	+= \
 		-I$(DIST)/public/nss \
 		$(NULL)
diff --git a/security/manager/pki/src/moz.build b/security/manager/pki/src/moz.build
index 69d18204687..d7da5f75ee7 100644
--- a/security/manager/pki/src/moz.build
+++ b/security/manager/pki/src/moz.build
@@ -17,3 +17,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'pippki'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/services/crypto/component/Makefile.in b/services/crypto/component/Makefile.in
index 432fe7e5f2c..466dfbf2ea4 100644
--- a/services/crypto/component/Makefile.in
+++ b/services/crypto/component/Makefile.in
@@ -9,8 +9,6 @@ VPATH     = @srcdir@
 
 include $(DEPTH)/config/autoconf.mk
 
-FAIL_ON_WARNINGS := 1
-
 EXPORT_LIBRARY := 1
 LIBXUL_LIBRARY := 1
 MOZILLA_INTERNAL_API := 1
diff --git a/services/crypto/component/moz.build b/services/crypto/component/moz.build
index 7c322ecd6cd..2801204c5b2 100644
--- a/services/crypto/component/moz.build
+++ b/services/crypto/component/moz.build
@@ -20,3 +20,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'services-crypto'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/toolkit/components/autocomplete/Makefile.in b/toolkit/components/autocomplete/Makefile.in
index 78a8104e375..e06e5e62274 100644
--- a/toolkit/components/autocomplete/Makefile.in
+++ b/toolkit/components/autocomplete/Makefile.in
@@ -11,6 +11,4 @@ include $(DEPTH)/config/autoconf.mk
 
 EXPORT_LIBRARY = 1
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
diff --git a/toolkit/components/autocomplete/moz.build b/toolkit/components/autocomplete/moz.build
index 6b28849d106..457808f5893 100644
--- a/toolkit/components/autocomplete/moz.build
+++ b/toolkit/components/autocomplete/moz.build
@@ -24,3 +24,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'tkautocomplete'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/toolkit/components/downloads/Makefile.in b/toolkit/components/downloads/Makefile.in
index 2ac02f98548..afe129da352 100644
--- a/toolkit/components/downloads/Makefile.in
+++ b/toolkit/components/downloads/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME = download_s
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
 CXXFLAGS += $(TK_CFLAGS) -DGOOGLE_PROTOBUF_NO_RTTI
diff --git a/toolkit/components/downloads/moz.build b/toolkit/components/downloads/moz.build
index da4f7ddb96e..94119ab94c8 100644
--- a/toolkit/components/downloads/moz.build
+++ b/toolkit/components/downloads/moz.build
@@ -35,3 +35,6 @@ if not CONFIG['MOZ_SUITE']:
         'nsDownloadManagerUI.js',
         'nsDownloadManagerUI.manifest',
     ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/toolkit/components/perf/Makefile.in b/toolkit/components/perf/Makefile.in
index 8d07f3ae852..d06b73bf764 100644
--- a/toolkit/components/perf/Makefile.in
+++ b/toolkit/components/perf/Makefile.in
@@ -11,8 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBXUL_LIBRARY = 1
 EXPORT_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 LOCAL_INCLUDES := \
   -I$(topsrcdir)/js/xpconnect/loader \
   $(NULL)
diff --git a/toolkit/components/perf/moz.build b/toolkit/components/perf/moz.build
index f619a7dc60a..66c590cf301 100644
--- a/toolkit/components/perf/moz.build
+++ b/toolkit/components/perf/moz.build
@@ -15,3 +15,6 @@ LIBRARY_NAME = 'jsperf'
 EXTRA_JS_MODULES += [
     'PerfMeasurement.jsm',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/toolkit/components/places/tests/cpp/Makefile.in b/toolkit/components/places/tests/cpp/Makefile.in
deleted file mode 100644
index 4b4ffa22ee5..00000000000
--- a/toolkit/components/places/tests/cpp/Makefile.in
+++ /dev/null
@@ -1,14 +0,0 @@
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-DEPTH     = @DEPTH@
-topsrcdir = @top_srcdir@
-srcdir    = @srcdir@
-VPATH     = @srcdir@
-relativesrcdir = @relativesrcdir@
-FAIL_ON_WARNINGS = 1
-
-include $(DEPTH)/config/autoconf.mk
-
-include $(topsrcdir)/config/rules.mk
diff --git a/toolkit/components/places/tests/cpp/moz.build b/toolkit/components/places/tests/cpp/moz.build
index 2d7b3630ef7..7b697409ecc 100644
--- a/toolkit/components/places/tests/cpp/moz.build
+++ b/toolkit/components/places/tests/cpp/moz.build
@@ -10,3 +10,5 @@ CPP_UNIT_TESTS += [
     'test_IHistory.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/toolkit/components/telemetry/Makefile.in b/toolkit/components/telemetry/Makefile.in
index 7a33bb56cf6..8c12c41af98 100644
--- a/toolkit/components/telemetry/Makefile.in
+++ b/toolkit/components/telemetry/Makefile.in
@@ -14,8 +14,6 @@ include $(topsrcdir)/config/makefiles/rcs.mk
 
 LIBXUL_LIBRARY = 1
 EXPORT_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 LIBRARY_NAME = telemetry
 MSVC_ENABLE_PGO := 1
 
diff --git a/toolkit/components/telemetry/moz.build b/toolkit/components/telemetry/moz.build
index c79dc500830..a33372fab88 100644
--- a/toolkit/components/telemetry/moz.build
+++ b/toolkit/components/telemetry/moz.build
@@ -36,3 +36,6 @@ EXTRA_JS_MODULES += [
     'TelemetryStopwatch.jsm',
     'ThirdPartyCookieProbe.jsm',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/toolkit/components/url-classifier/Makefile.in b/toolkit/components/url-classifier/Makefile.in
index f8a78915b07..82db7d8136f 100644
--- a/toolkit/components/url-classifier/Makefile.in
+++ b/toolkit/components/url-classifier/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 LOCAL_INCLUDES = \
   -I$(srcdir)/../build \
   $(SQLITE_CFLAGS) \
diff --git a/toolkit/components/url-classifier/moz.build b/toolkit/components/url-classifier/moz.build
index 22828490c2f..85c9f7f10a3 100644
--- a/toolkit/components/url-classifier/moz.build
+++ b/toolkit/components/url-classifier/moz.build
@@ -47,3 +47,6 @@ LIBRARY_NAME = 'urlclassifier_s'
 EXTRA_JS_MODULES += [
     'SafeBrowsing.jsm',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/toolkit/identity/Makefile.in b/toolkit/identity/Makefile.in
index ff9d29f6923..0e964800849 100644
--- a/toolkit/identity/Makefile.in
+++ b/toolkit/identity/Makefile.in
@@ -9,8 +9,6 @@ VPATH     = @srcdir@
 
 include $(DEPTH)/config/autoconf.mk
 
-FAIL_ON_WARNINGS := 1
-
 LIBXUL_LIBRARY = 1
 EXPORT_LIBRARY = 1
 
diff --git a/toolkit/identity/moz.build b/toolkit/identity/moz.build
index 24d05c71456..40d61c327e4 100644
--- a/toolkit/identity/moz.build
+++ b/toolkit/identity/moz.build
@@ -31,3 +31,6 @@ EXTRA_JS_MODULES += [
     'Sandbox.jsm',
     'jwcrypto.jsm',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/toolkit/system/gnome/Makefile.in b/toolkit/system/gnome/Makefile.in
index 64efc3e8408..70ab32ecfaf 100644
--- a/toolkit/system/gnome/Makefile.in
+++ b/toolkit/system/gnome/Makefile.in
@@ -11,8 +11,6 @@ include $(DEPTH)/config/autoconf.mk
 
 FORCE_SHARED_LIB = 1
 IS_COMPONENT	= 1
-FAIL_ON_WARNINGS = 1
-
 EXTRA_DSO_LDOPTS += \
 		$(XPCOM_GLUE_LDOPTS) \
 		$(XPCOM_FROZEN_LDOPTS) \
diff --git a/toolkit/system/gnome/moz.build b/toolkit/system/gnome/moz.build
index b535a980422..76b7be19b92 100644
--- a/toolkit/system/gnome/moz.build
+++ b/toolkit/system/gnome/moz.build
@@ -28,3 +28,5 @@ if CONFIG['MOZ_ENABLE_GIO']:
 
 LIBRARY_NAME = 'mozgnome'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/tools/profiler/Makefile.in b/tools/profiler/Makefile.in
index e89bfbe79a1..181f8462420 100644
--- a/tools/profiler/Makefile.in
+++ b/tools/profiler/Makefile.in
@@ -25,9 +25,6 @@ endif
 
 EXPORT_LIBRARY  = 1
 LIBXUL_LIBRARY  = 1
-ifndef _MSC_VER
-FAIL_ON_WARNINGS = 1
-endif # !_MSC_VER
 
 # Uncomment for better debugging in opt builds
 #MOZ_OPTIMIZE_FLAGS += -O0 -g
diff --git a/tools/profiler/moz.build b/tools/profiler/moz.build
index aefb0c79376..02e2fa0eb9f 100644
--- a/tools/profiler/moz.build
+++ b/tools/profiler/moz.build
@@ -5,6 +5,9 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 if CONFIG['MOZ_ENABLE_PROFILER_SPS']:
+    FAIL_ON_WARNINGS = not CONFIG['_MSC_VER']
+
+
     MODULE = 'profiler'
     LIBRARY_NAME = 'profiler'
     XPIDL_SOURCES += [
diff --git a/uriloader/base/Makefile.in b/uriloader/base/Makefile.in
index dc9ad52d474..5742e8f437b 100644
--- a/uriloader/base/Makefile.in
+++ b/uriloader/base/Makefile.in
@@ -12,7 +12,5 @@ include $(DEPTH)/config/autoconf.mk
 
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY  = 1
-FAIL_ON_WARNINGS = 1
-
 include $(topsrcdir)/config/rules.mk
 
diff --git a/uriloader/base/moz.build b/uriloader/base/moz.build
index 3aad3281d2b..cc0f3e133c6 100644
--- a/uriloader/base/moz.build
+++ b/uriloader/base/moz.build
@@ -30,3 +30,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'uriloaderbase_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/uriloader/exthandler/Makefile.in b/uriloader/exthandler/Makefile.in
index 94a4dbe0b25..a0d397421f4 100644
--- a/uriloader/exthandler/Makefile.in
+++ b/uriloader/exthandler/Makefile.in
@@ -35,9 +35,6 @@ VPATH		:= $(srcdir) $(srcdir)/$(OSDIR)
 
 LIBRARY_NAME    = exthandler_s
 LIBXUL_LIBRARY  = 1
-FAIL_ON_WARNINGS = 1
-
-
 ifeq ($(MOZ_WIDGET_TOOLKIT),cocoa)
 
 CMMSRCS	= nsOSHelperAppService.mm \
diff --git a/uriloader/exthandler/moz.build b/uriloader/exthandler/moz.build
index 8c2277859b4..0b6afeff7f7 100644
--- a/uriloader/exthandler/moz.build
+++ b/uriloader/exthandler/moz.build
@@ -122,3 +122,6 @@ EXTRA_COMPONENTS += [
 IPDL_SOURCES += [
     'PExternalHelperApp.ipdl',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/uriloader/prefetch/Makefile.in b/uriloader/prefetch/Makefile.in
index a64befb2dae..4d8b2e0afc5 100644
--- a/uriloader/prefetch/Makefile.in
+++ b/uriloader/prefetch/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME	= prefetch_s
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS = 1
-
 LOCAL_INCLUDES = \
 		-I$(topsrcdir)/content/base/src \
 		-I$(topsrcdir)/content/events/src \
diff --git a/uriloader/prefetch/moz.build b/uriloader/prefetch/moz.build
index b4c0d936f3d..74b30123aeb 100644
--- a/uriloader/prefetch/moz.build
+++ b/uriloader/prefetch/moz.build
@@ -32,3 +32,6 @@ CPP_SOURCES += [
 IPDL_SOURCES += [
     'POfflineCacheUpdate.ipdl',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/view/src/Makefile.in b/view/src/Makefile.in
index d8c8fbdb533..e08b0e598b3 100644
--- a/view/src/Makefile.in
+++ b/view/src/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 MSVC_ENABLE_PGO := 1
 LIBXUL_LIBRARY	= 1
-FAIL_ON_WARNINGS := 1
-
 include $(topsrcdir)/config/rules.mk
 
 LOCAL_INCLUDES  = \
diff --git a/view/src/moz.build b/view/src/moz.build
index c362d3c40d5..9d67e943bfd 100644
--- a/view/src/moz.build
+++ b/view/src/moz.build
@@ -13,3 +13,5 @@ CPP_SOURCES += [
 
 LIBRARY_NAME = 'gkview_s'
 
+FAIL_ON_WARNINGS = True
+
diff --git a/webapprt/gtk2/Makefile.in b/webapprt/gtk2/Makefile.in
index 969557ed3b2..b74ed3e54a6 100644
--- a/webapprt/gtk2/Makefile.in
+++ b/webapprt/gtk2/Makefile.in
@@ -6,8 +6,6 @@ DEPTH = @DEPTH@
 topsrcdir = @top_srcdir@
 srcdir = @srcdir@
 VPATH = @srcdir@
-FAIL_ON_WARNINGS := 1
-
 include $(DEPTH)/config/autoconf.mk
 
 LOCAL_INCLUDES += \
diff --git a/webapprt/gtk2/moz.build b/webapprt/gtk2/moz.build
index 890b5961a69..1b989dd82d0 100644
--- a/webapprt/gtk2/moz.build
+++ b/webapprt/gtk2/moz.build
@@ -9,3 +9,6 @@ PROGRAM = 'webapprt-stub'
 CPP_SOURCES += [
     'webapprt.cpp',
 ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/widget/android/Makefile.in b/widget/android/Makefile.in
index 0e9513ab4ea..d2f76c6bb2a 100644
--- a/widget/android/Makefile.in
+++ b/widget/android/Makefile.in
@@ -12,8 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 LIBRARY_NAME    = widget_android
 EXPORT_LIBRARY  = 1
 LIBXUL_LIBRARY  = 1
-FAIL_ON_WARNINGS := 1
-
 ifdef MOZ_WEBSMS_BACKEND
 DEFINES += -DMOZ_WEBSMS_BACKEND
 endif
diff --git a/widget/android/moz.build b/widget/android/moz.build
index 51640c2b618..7d62bcd8f4d 100644
--- a/widget/android/moz.build
+++ b/widget/android/moz.build
@@ -38,3 +38,5 @@ CPP_SOURCES += [
     'nsWindow.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/widget/gonk/nativewindow/Makefile.in b/widget/gonk/nativewindow/Makefile.in
index 098906cb652..f9355a69659 100644
--- a/widget/gonk/nativewindow/Makefile.in
+++ b/widget/gonk/nativewindow/Makefile.in
@@ -20,7 +20,6 @@ include $(DEPTH)/config/autoconf.mk
 
 LIBRARY_NAME     = nativewindow
 LIBXUL_LIBRARY   = 1
-FAIL_ON_WARNINGS := 1
 STL_FLAGS=
 
 include $(topsrcdir)/config/rules.mk
diff --git a/widget/gonk/nativewindow/moz.build b/widget/gonk/nativewindow/moz.build
index 25617adb25a..da8d1d239ef 100644
--- a/widget/gonk/nativewindow/moz.build
+++ b/widget/gonk/nativewindow/moz.build
@@ -32,3 +32,5 @@ if CONFIG['MOZ_B2G_CAMERA'] or CONFIG['MOZ_OMX_DECODER']:
         'GonkNativeWindowClientICS.cpp',
     ]
 
+FAIL_ON_WARNINGS = True
+
diff --git a/widget/gtk2/Makefile.in b/widget/gtk2/Makefile.in
index 8f97cf03c1f..415d617b0bd 100644
--- a/widget/gtk2/Makefile.in
+++ b/widget/gtk2/Makefile.in
@@ -18,8 +18,6 @@ endif
 
 EXPORT_LIBRARY	= 1
 LIBXUL_LIBRARY = 1
-FAIL_ON_WARNINGS = 1
-
 NATIVE_THEME_SUPPORT = 1
 
 
diff --git a/widget/gtk2/moz.build b/widget/gtk2/moz.build
index 00fbb5c894b..8e76427ead2 100644
--- a/widget/gtk2/moz.build
+++ b/widget/gtk2/moz.build
@@ -53,3 +53,6 @@ if CONFIG['MOZ_X11']:
         'nsClipboard.cpp',
         'nsDragService.cpp',
     ]
+
+FAIL_ON_WARNINGS = True
+
diff --git a/widget/tests/Makefile.in b/widget/tests/Makefile.in
index 2c47fcc61b1..d90c64376d4 100644
--- a/widget/tests/Makefile.in
+++ b/widget/tests/Makefile.in
@@ -8,8 +8,6 @@ topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
 relativesrcdir  = @relativesrcdir@
-FAIL_ON_WARNINGS = 1
-
 include $(DEPTH)/config/autoconf.mk
 
 ifeq ($(MOZ_WIDGET_TOOLKIT),windows)
diff --git a/widget/tests/moz.build b/widget/tests/moz.build
index 6bd1dfbc649..42fcf4e4532 100644
--- a/widget/tests/moz.build
+++ b/widget/tests/moz.build
@@ -12,3 +12,5 @@ CPP_UNIT_TESTS += [
     'TestAppShellSteadyState.cpp',
 ]
 
+FAIL_ON_WARNINGS = True
+